Won’t invasives just go away?

The short answer: no. A variety of fac-tors, from global commerce to climatechange, are making it ever easier for or-ganisms to move around and find newhomes. The rate of species introduc-

tions has accelerated in recent decadesand increasing numbers of non-nativespecies are becoming established inWisconsin.

Scientists call this “biotic homoge-nization” — the global mixing of plants

and animals from around the world.Over the millennia, each region of theworld evolved its own unique flora andfauna. But now that people and goodsmove around more quickly and freelythan ever before, remote places are nolonger so isolated. It is not unusual forspecies to jump from one continent toanother, much less across state lines.Some are carried intentionally, as newlandscape plants or sport fish. Otherscome in as hitchhikers in wood prod-ucts, forage, soil or boating equipment.

This number of jet-setting species islikely to increase, which means thosedoomsday headlines about the next biginvader are probably going to keep com-ing. Even if we figure out ways to con-trol today’s invasive species, there willlikely be more arriving tomorrow,dumped from the ballast water of ocean-going ships, swimming up a manmadechannel, or creeping up from southernstates as the climate becomes warmer.

Once they are here, invasive speciesare difficult — often impossible — to

Reasonable expectations

Practical advice to recognize and minimize the consequences of invasive species.

Julia Solomon

SPECIAL REPORT

If another article about the perils of plant and animal invadersmakes you sigh, shake your head, and skip to the next story, you’re not alone.

Invasive species have received a lot of press in the past fewyears, most of it bad and some downright alarming. From the emeraldash borer to the Asian carp to the giant hogweed, it seems there is al-ways a new monster lurking at the borders just waiting for the chanceto wreak havoc on our beloved woods and waters.

It can be tempting to tune out all this bad news and assume theproblem will go away, that someone else will fix it, or worse, that it’shopeless. Each one of these assumptions is understandable, but noneis accurate, and none brings us any closer to a solution.

It’s time for an honest look at the reality of invasive species in Wis-consin, and examining these assumptions is a good place to start.

Reasonable expectations

MANAGING INVASIVE PLANTS

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eradicate completely. Unfortunately, theproblem of invasives is here to stay.

This fact, though sobering, shouldnot be cause for despair. Yes, we are infor a long haul. No, there are not likelyto be miraculous quick-fix solutions.And, yes, these unwelcome guests willaffect Wisconsin’s environment — in-deed, they already have. But those im-pacts do not need to be catastrophic.Not every lake, forest or bog is destinedto be overrun. With diligent monitoringand containment, many of our ecologi-cal gems can be protected.

Strategic investment in prevention,early detection, and control of invasivespecies will help the natural and humancommunities of Wisconsin adapt to thereality of life in the biotic fast lane. Wecan learn to live with some inevitablechanges while preserving what we love.

Isn’t it somebody else’s job?

Investment is a loaded word. It meansnot only money, but time: hours spentpulling garlic mustard from a neighbor-hood forest, inspecting trees for newpests, cleaning zebra mussels off drink-ing water intakes. It also means devot-ing dollars to everything from scientificresearch to signs at boat launches andstate parks.

Confronting the reality of invasivespecies is a daunting task — surelythere is someone who is responsible fordealing with the problem? There is, andit is all of us.

It’s easy to place blame for invasivespecies and there’s often a lot of finger-pointing when these organisms are dis-covered: We have invasive plants in ourlakes because visiting boaters bringthem in. Emerald ash borers arrive onfirewood visitors bring from otherstates. New species arrive in the GreatLakes because federal ballast water reg-ulations aren’t strict enough. Scientificresearchers should come up with moreeffective methods of control. The cost ofinvasives should be borne by the town,the state, the federal government, notby outdoor users.

Whether or not these claims are true,they miss the point. Invasive species area long-term, large-scale problem thatwill not be solved by pointing fingers.True solutions will require many part-ners, substantial funding, and, yes, a lotof volunteer hours. It’s an investmentwe will all have to make. Governmentofficials, resource managers, researchersand local citizens all have a role to play.

What’s the use?

In some ways, this is the easiest ques-tion to answer. Throwing up our handsin surrender will not slow the spread.Keeping invasive species at bay can becostly and tiring, but when your backaches from pulling buckthorn, stop fora moment and imagine the alternative.

Wisconsinites share a deep love forour natural places and the nativespecies that make this land feel like

home. We will not stand aside to watchour flora and fauna be choked out byinvasive species. We cannot afford to.Three of the state’s top industries —agriculture, tourism and forestry — alldepend on natural resources and arethreatened by invaders.

But the reasons for working againstinvasives go far beyond economics. Rit-uals such as watching for the first trilli-um bloom and pulling panfish from a familiar lake are part of Wisconsin culture, and we care about them pas-sionately. Invasive species put these rituals at risk. Ultimately, it is our loveof home that motivates citizens andpolicymakers to confront the problemof invasives with realism, persistenceand optimism.

That optimism is not unfounded. Asin the rest of life, bad news about inva-sive species tends to grab the headlineswhile successes often slip by unnoticed.In these pages you will find stories ofthe hard work going on around thestate and learn about the progress beingmade. You’ll also find out about themany ways you can help protect Wis-consin’s native species.

Take heart, and read on!

Julia Solomon is an educator explaining aquaticinvasive species issues for the Department ofNatural Resources and UW-Extension.

1 Reasonable expectationsPractical advice and positivedirections to recognize and minimize the consequences ofinvasive species.

3 Sentinels to sound the alarmYour rapid identification of the latestgroup of invasive plant species toplague Wisconsin may stem an unwelcome infestation.

7 Unwelcome guests, unwelcome costs

8 Beetle brigades and weevil squadronsIntroducing carefully selected predators to rein in invasive plantscan work, but human vigilance is still the best defense.

12 Invasion at a slow crawlExotic earthworms are nosing intonorthern forests at an unnaturalpace.

14 Only YOU can stop the invasion

15 Alternative plants for landscaping

16 Keeping up to speed

Understanding invasive species provides many teaching moments to identify plants and look-alikes, learnhow they spread, appreciate different controls and value the contributions of volunteers.

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Sentinels to sound the alarmYour rapid identification of the latest group of invasive plant species to plague Wisconsin may stem an unwelcome infestation. Kelly Kearns and Nicole Hayes

These alert volunteers keep their eyes open, andthey’ve seen plenty. Thanks to their observations and re-ports, populations of unwelcome invasives we alerted youto in 2006, including Japanese hedge parsley, common andcut-leaf teasel, European marsh thistle, flowering rush,Japanese hops and black swallow-wort, have been identi-fied. Control work is underway on a number of the plantsfound in forested areas, supported by a grant from the U.S.Forest Service and the diligent effort of several landown-ers, private contractors and community organizations.Giant hogweed infestations have spawned the develop-ment of a Cooperative Weed Management Area to contain

this plant on both sides of the Wisconsin/Michigan border. Fortunately, we do not yet know of any populations in Wis-

consin of other plants in our past alert — Japanese stilt grass,spreading hedge parsley, pale swallow-wort, wineberry, Euro-pean frog-bit, hydrilla or water chestnut. Keep watching forthese species — they may show up at any time. The key to pre-vention is early spotting and prompt removal.

Here’s a list of a new group of plants we expect to startspreading in Wisconsin very soon. Please keep an eye out forthese invasives, and if you find any of these species, take aphoto, collect a voucher specimen and quickly report the find tothe Department of Natural Resources.

It’s a basic defense technique right out of the Middle Ages: Put more eyes on thelookout for invaders, and the interlopers will have less of a chance to scale thecastle walls. When the DNR and the UW-Madison Herbarium put out a callfor volunteers to join Wisconsin’s Invasive Plants of the Future initiative — a

program with the aim of locating and controlling populations of new invasive plantslikely to cause trouble in the future — many people took up the sentry posts, scout-ing their own backyards, nearby fields, and favorite parks, lakes and forests for trou-blesome species.

Sentinels to sound the alarm

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Tree of heaven (Ailanthus altissima)

Ironically named, this weedy tree growsfast, adding three feet a year and reach-ing up to 80 feet. It is primarily found inurban areas in southern Wisconsin.However, it is rapidly spreading inforests in the states to our south and east.In forests it quickly reaches the canopyand shades out mature trees. Leaves andflowers may cause contact dermatitis insome people. It also produces toxins thatcan prevent the establishment of otherplant species. In cities, its aggressive rootsystem damages sewers, sidewalks andfoundations. When cut, it produces suck-ers and stump sprouts. A single tree canbear up to 325,000 wind-dispersed seedseach year. The most distinctive character-istics of this deciduous tree are its foulodor and its four-foot-long compoundleaves.

Please report any Ailanthus found inforested areas, including urban parks.

Oriental bittersweet (Celastrus orbiculata)

Easily confused with the native Ameri-can bittersweet, Oriental bittersweet is aserious threat to grasslands, woodlandedges, forests, roadsides and beaches.This woody climbing vine is capable ofover-topping tall trees, shading, gir-dling, and eventually pulling themdown. Oriental bittersweet vines growup to 60 feet high and four inches in diameter. The fruit’s yellow membraneeventually splits to reveal a red innerfruit. Birds and mammals disperse theseeds. There are a number of scattered

infestations known in Wisconsin, but itis not yet widespread. Wreaths and flo-ral arrangements with bittersweet orother seeds should be disposed of in thetrash rather then in compost or brushpiles. Be sure you’ve identified the cor-rect bittersweet: our native Americanbittersweet has leaves with a more ta-pered tip and larger fruit clusters at theends of stems, and the fruits are pro-duced in small clusters at the leaf axils.

Porcelain berry (Ampelopsis brevipedunculata)

Sometimes planted as an ornamental,porcelain berry is a deciduous, woodyvine in the grape family. It can be ex-tremely aggressive, shading out nativevegetation by blanketing the ground,and climbing trees and shrubs using itstendrils. In forests in the mid-Atlanticstates it grows rapidly along forestedges, trails, roadsides, riparian andopen areas. Wildlife eat the distinctivepink, blue and lavender fruits, then dis-perse the seeds. We know of only a fewinfestations in Wisconsin, although it ismuch more abundant to the south. Re-ports indicate only the green-leaved va-riety is invasive; the variegated cultivarappears to be benign.

Kudzu (Pueraria lobata)

Notorious as “The vine that ate theSouth,” kudzu is known for its ability tocover large trees, forest edges, utilitylines, billboards, abandoned houses andanything in its path. Nearby vegetationdies for lack of sunlight. A single kudzu

root can produce up to 30 vines capableof growing up to a foot a day and 60 feetper summer. It quickly girdles and blan-kets shrubs and trees, breaking branchesand uprooting entire trees under itsweight. Kudzu reproduces via runners,rhizomes, vines that root at the nodes,and hard-coated seeds dispersed bywind, water and animals. This perenniallegume has large three-part leaves andreddish-purple flowers that produceflat, brown, pea-like pods. Although nopopulations have been found in Wiscon-sin, recent research showed the north-ernmost population has been producingviable seed. Those plants were located inEvanston, Illinois — about 30 milessouth of the border.

Japanese honeysuckle (Lonicera japonica)

This semi-evergreen woody vine re-sembles native honeysuckle vines, butit has pairs of white, cream or pinkflowers, hairy opposite leaves, andproduces purplish black berries. Japan-ese honeysuckle spreads in woodlandedges, floodplains, fields and road-sides. The vines typically grow six toten feet in height, but can reach up to30 feet, forming dense intertwiningmats that outcompete native vegeta-tion for light, water and nutrients, andtopple shrubs and trees. Japanese hon-eysuckle reproduces via undergroundstems (rhizomes) and seed dispersedby birds. Toxins from the vine may in-hibit the regeneration of some trees. Itis abundant in central Illinois andseems to be expanding northward.There may be ornamental cultivars thatare not invasive.

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Baby’s breath (Gypsophila paniculata)

One of the most commonly used plantsin the floriculture industry, baby’sbreath is troublesome only when it getsinto Great Lakes dunes. On these shoresit can form a huge taproot and stabilizenaturally shifting sand dunes to thepoint of significantly changing the opendune habitat certain native plants need,as is the case with the federally threat-ened dune thistle (Cirsium pitcheri) inMichigan. It is currently invading theMichigan shore of Lake Michigan, buthas not yet been found on Wisconsin’swest shore of the lake. Baby’s breath is aperennial forb growing up to three feettall with a thick, deep taproot andbranched stem. It has narrow oppositeleaves and white or pink flowers withfive petals.

Japanese knotweed (Polygonum cuspidatum, syn.

Fallopia japonica)

Often erroneously referred to as “Mexi-can bamboo,” this semi-woody perenni-al in the buckwheat family is found inurban areas where it was planted yearsago. It spreads rapidly by rhizomes,forming large, dense thickets that elimi-nate native vegetation and wildlifehabitat. Although it is already some-what widespread in much of the state, itis generally not yet in the habitatswhere it is likely to become extremelyinvasive. Once it gets into the shore of ariver, stream or lake, knotweed can

spread by root fragments, formingthickets that line the shore for miles andcause extensive shoreline erosion. Onceestablished, large dense stands are diffi-cult to eradicate. Thick bamboo-likestems reaching six to eight feet, withlarge heart-shaped leaves and terminallacy clusters of white flowers make itvery easy to identify this plant.

Poison hemlock (Conium maculatum)

One of the most poisonous plants in theworld, poison hemlock is a biennialforb in the parsley family. In Indianaand Illinois it is abundant along road-sides, from which it spreads into moistsites such as stream banks, wet mead-ows and ditches, although it can thrivein drier sites. Only a few patches havebeen reported in Wisconsin, although itis spreading in some sites and is likelyto become more abundant soon. Tallerthan most plants in this family, it canreach over seven feet and has pinnatelycompound leaves, green stems withpurple or black spots and multiple um-bels of white flowers.

Wild chervil (Anthriscus sylvestris)

Although not currently widespread inthe upper Midwest, wild chervil, nativeto Europe, is prolific in areas where it isfound. It has spread rapidly in thenortheast in recent years. While report-edly not a problem in cultivated fields,this biennial or short-lived perennial

forb in the parsley family competes ag-gressively with forage crops for light,water and nutrients, and shades outsurrounding vegetation. It can alsospread along roadsides into grasslandsand open woods. It has finely com-pound leaves and a taproot. In the sec-ond year, the plants produce hollowflower stems, usually three to four feettall (it can reach six feet). Tiny whiteflowers form in umbels, like umbrellas.

Hill mustard (Bunias orientalis)

A new invader just recently sighted inWisconsin, hill mustard appears to in-vade open grassland sites, rapidlyforming dense patches that excludeother plants. Although it can be a bien-nial, the plants known in southern Wis-consin appear to be perennials. From adistance, this plant looks like the com-mon yellow rocket with its bright yel-low, four petaled flowers. However, theleaves are up to twelve inches long onthe lower part of the flowering stem,getting smaller as they go up the stem.They look somewhat like dandelionleaves. The warty bumps on the stemare distinctive.

Pond water-starwort (Callitriche stagnalis)

This floating aquatic plant has beenfound in states in the northeast, north-west and a few sites in Wisconsin. Pondwater-starwort grows in ponds, marsh-es and streams. It is capable of creatinglocally dense mats of vegetation that may crowd out native aquatic

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vegetation. The floating stems havesmall, densely packed oval leaves thatform overlaid crosses and tiny incon-spicuous flowers.

Yellow floating heart (Nymphoides peltata)

Looking like a small yellow water lily,yellow floating heart is a floatingaquatic perennial. This plant often isused as an ornamental in water gar-dens. It can form large floating mats inslow-moving rivers, lakes, reservoirs,ponds and swamps. Infestations occurin northern Indiana and northern Illi-nois, but have not yet been found inWisconsin.

Brazilian waterweed (Egeria densa)

Sold for use in aquariums or water gar-dens, Brazilian waterweed can formstands that crowd out native aquaticplants in lakes, rivers, ponds andsprings. It provides poor habitat forfish and waterfowl, interferes withrecreational activities, and supportslarge populations of mosquitoes. It hasbeen found as far north as Oregon, Illi-nois and Vermont. During winter, itsurvives along the bottom and resumesgrowing when waters reach 50 degreesFahrenheit. It is a submerged speciesthat resembles our native elodea, butwith more showy emergent flowerswith three white petals and a yellowcenter.

Still on the watch listThe following invasive species should also be report-ed. To read more about the species listed below andsee photos of each, review a copy of the June 2006story in Wisconsin Natural Resources magazine,“Green invaders on the horizon” by David Eagan. Re-view it online at www.wnrmag.com/stories/2006/jun06/invade.htm

Report the following plants wherever they are found:Mile-a-minute (Polygonum perfoliatum) Chinese yam (Dioscorea oppositifolia) Japanese stilt grass (Microstegium vimineum)Spreading hedge parsley (Torilis arvensis)Black swallow-wort (Vincetoxicum nigrum)Pale swallow-wort (Vincetoxicum rossicum, syn. Cynanchum rossicum)Wineberry (Rubus phoenicolasius)Japanese hops (Humulus japonicus)Giant hogweed (Heracleum mantegazzianum)European frog-bit (Hydrocharis morsus-ranae)Hydrilla (Hydrilla verticillata)Water chestnut (Trapa natans)

Report the following plants if found in these habitats:• Tree of heaven (Ailanthus altissima)

forests and woodland edges• Oriental bittersweet (Celastrus orbiculata)

forests, woodland edges, grasslands• Porcelain-berry (Ampelopsis brevipedunculata)

forests, woodland edges and grasslands• Japanese honeysuckle (Lonicera japonica)

any plants growing in the wild• Japanese hedge parsley (Torilis japonicus)

forests and woodland edges• Lesser celandine (Ranunculus ficaria)

forests and woodland edges• Common teasel

(Dipsacus fullonum subsp. sylvestris)wetlands and native or restored prairies

• Cut-leaf teasel (Dipsacus laciniatus) wetlands and native or restored prairies

• Japanese knotweed(Polygonum cuspidatum, syn. Fallopia japonica) wetlands, lakes, streams or shorelines

• European marsh thistle (Cirsium palustre) wetlands, barrens and forests

• Flowering rush (Butomus umbellatus) wetlands, lakes, streams or shorelines

• Baby’s breath (Gypsophila paniculata) Great Lakes dunes or beaches

Please report any occurrences of these speciesalong with a detailed description of the location,photo and/or voucher specimen. Send to:KellyKearns, Endangered Resources Program, WI DNR,101 S. Webster St., Madison, WI 53707-7921,608-267-5066, kelly.kearns@wisconsin.gov

Kelly Kearns manages plant conservation programsfor DNR’s Bureau of Endangered Resources. NicoleHayes studies native and exotic invertebrates at theUW-Madison Center for Limnology.

Fanwort (Cabomba caroliniana)

A submersed or sometimes floatingaquatic perennial, fanwort is sometimessold for use in aquariums. It often findsits way into local ponds and streamswhere it forms dense stands, crowdingout other vegetation, clogging streamsand interfering with recreational uses.As with many aquatic plants, a smallfragment can regenerate a whole plant.Considered weedy even in its nativerange, it has created severe nuisanceconditions as far north as New York,Michigan and Oregon. It has both sub-mersed and floating leaves of differentshapes. The white flowers are heldabove the water on a stalk.

Parrot feather (Myriophyllum aquaticum)

Closely related to and easily mistakenfor Eurasian water-milfoil, parrot feath-er is an aquatic perennial in the milfoilfamily. Commonly sold by the aquari-um trade — often under other names —parrot feather has both submersed andemergent leaves. Small fragments canquickly grow into dense mats, provid-ing ideal mosquito larvae habitat andshading out native algae that serve asthe basis for the aquatic food chain. In-festations can also hinder water andboat movement in lakes, ponds andstreams. It has naturalized throughoutthe southern states and northward asfar as Idaho, Washington and NewYork. Research studies showed it couldsurvive average Minneapolis wintertemperatures.

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Making a positive ID of bad actors

Voucher specimens are plant samples thatprovide physical evidence to confirm that aninvasive species is present in a specific loca-tion. Botanists examine these leaves, stems,flowers, roots and fruits to verify species iden-tification.

When collecting a fresh specimen makesure you wear gloves as some plant stemsand juices contain irritants. Also take de-tailed and close-up photos showing howwidespread the stand of plants may be andclose-ups that clearly show plant features likeflowers, general shape, seed heads, leafshape and arrangement. Sometimes close,clear photographs are sufficient to identifyplants that have distinctive leaves, flowersand fruits. In photos, place a coin, pencil orruler for scale. If you can send a specimenand take a photo, all the better.

Fill out a shor t invasive plant repor t that pinpoints where the plant was collected,estimates how widespread an area the plantcovers and provides a description of the habi-tat type (forest, field, prairie, wetland, openwater, lawn, garden, etc.). The DNR’s invasiveplants website details information needed inthese accounts and provides a repor tingform. Visit the website dnr.wi.gov/invasives/futureplants/reporting.htm

To send a dried sample, press the plantspecimen carefully between several layers ofnewspapers sandwiched between sheets ofcardboard and weighted down. Change thenewspapers frequently until the plant is dry.Ship by enclosing the dried specimen be-tween pieces of cardboard in a large enve-lope. Fresh plant samples should be enclosedin a plastic bag with a moist paper towel andmailed right away.

Instructions for packaging and shippingfresh plants or dried samples are availablefrom Invasive Plant Reporting, DNR Endan-gered Resources Program, P.O. Box 7921, 101S. Webster St., Madison, WI 53707-7921. E-mail information and photos to: kelly.kearns@wisconsin.gov. You can also get questionsanswered about voucher samples or look formore details at this link on the DNR’s invasiveplant website: dnr.wi.gov/invasives/futureplants/voucher.htm.

Unwelcome guests,unwelcome costsJulia Solomon

If you’ve ever spent the day pulling garlic mustard from your woods or cleaningzebra mussels off the local beach, you know invasive species are a major pain.But did you know they are also a major expense? Invasive species cost the United States an estimated $120 billion dollars every

year (Pimentel 2005). If you’re wondering how that’s possible, take a minute tothink about some of the ways invasive species harm the economy as well as the en-vironment.

■ Prevention — Governments, private organizations and individual citizensall spend money to prevent the spread of invasive species. Costs associated withprevention programs range from printing educational materials to maintaininghigh-tech devices like the two-way electrical barrier that keeps Asian carp frommoving up the Illinois River into Lake Michigan and Great Lakes invaders fromheading downstream toward the Mississippi. Although prevention can be expensive, it is the most cost-effective way to combat invasive species.

■ Control — Invasive species can be controlled through mechanical methods(removal by hand or machine), chemical methods (herbicides and pesticides),and biological methods (introduction of pests, competitors or other organismsthat limit the spread of an invader). Although these techniques can be helpful inkeeping invaders in check, they can be costly and labor-intensive. Invasive con-trol is a long-term commitment and often requires repeated effort over manyyears. Complete eradication of invaders is seldom possible.

■ Equipment damage — Some invaders, such as zebra and quagga mus-sels, cause major damage to equipment and facilities. Power plants and watertreatment facilities spend millions every year to clean mussels off their water intake equipment. Invasive mussels can also damage recreational watercraft.

■ Lost revenue — Invasive weeds decrease crop and forage yields. Forestpests harm valuable timber stands. Invasive plants such as honeysuckle, buck-thorn and garlic mustard can prevent tree regeneration and reduce growth rateson older trees. In communities that rely on tourism and recreation as an econom-ic mainstay, the presence of troublesome invaders such as Eurasian water-milfoilcan devastate recreational resources and decrease tourism, reducing propertyvalues or causing local businesses to close.

■ Health hazards — Invasive species also pose health risks to humans andlivestock. Each year thousands of people are burned when they mow or brushup against wild parsnip. The toxins in this plant interact with skin and sunlightto cause burns that can take months to heal. Zebra and quagga mussels wash upon beaches by the thousands, where their razor-sharp shells are hazardous tobeachgoers. Spotted knapweed, leafy spurge, hoary alyssum and other plantscan be toxic to grazing cattle and horses.

■ Ecological harm — It’s impossible to put a dollar value on the ecologicaleffects of invasive species, but they are profound. Invasive species compete with— and sometimes consume — native species. They can make it harder for nativespecies to survive, and can cause significant population declines for rare and en-dangered species. In many cases they reduce the species diversity of the systemsthey invade. In Wisconsin, hundreds of lakes and millions of acres of land havebeen altered permanently by invading plants and animals.

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Introducing carefully selected predators to rein in invasive plants canwork, but human vigilance is still the best defense.

Brock Woods

Beetle brigades andweevil squadrons

To control non-native invasive plants established in our state, it seems we’vebeen sentenced to a life of hard labor. The continual digging, chopping, spray-ing and hauling — all the conventional control methods we find so laborious,expensive or disruptive — are they the only means we have to cope?

We may never be able to completely do away with shovels and herbicides, but wecan get some help from nature itself. By introducing the natural predators that keepthese plants in check in their own homelands, we can bring some invasives to heelhere in Wisconsin.

Biocontrol methods reconnect “old friends” in the hope that the introduced plantpredators will do here what they do at home — without attacking any of our nativeor economically valuable plants. The technique has met with great success againstpurple loosestrife, and it has slowed the spread of several other invasive species.

When infestations are small, purple loosestrife can be pulled by hand,but where larger stands are discovered, it makes sense to let beetlesthat specifically feed on this invasive plant help control the spread.

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In Wisconsin, most organisms intro-duced to control plants are insects thathave evolved to live on just one pestplant. These insects’ reproduction isclosely tuned to the plant’s uniquechemical makeup and growth habits,and they do not have the capacity tochange their own habits quickly. Thesetraits make host shifting difficult, ex-cept over long time periods. Both traitsare found in the four insect species cho-sen to control purple loosestrife. Theseinsects have been specific to their hostplant for more than a dozen years sincetheir initial introductions in 1994. It’sunlikely we will see these insects shiftto eating other plants for a very longtime, if ever.

Like the purple loosestrife insects,any new biocontrol organism must bewell-researched before it is released toensure it will not disrupt ecosystems. Iffollow-up monitoring also shows it tobe effective, the biocontrol speciesshould provide more benign and cheap-er control in the long run than most con-ventional methods, including herbicideuse. Once established, a biocontrol insect may be able to control a stand ofinvasive plants without constant replen-ishment. It is especially useful if it candisperse itself to new patches of the pestplant. All four loosestrife control insectshave not only passed all safety stan-dards, but have also established well in our temperate climate, and proven effective for over a decade. Some haveeven traveled as far as 10 miles to newinfestations.

Successful and efficient control ofmany invasive plants will, however, re-quire both biocontrol and conventionalcontrol. This is the case for purpleloosestrife, though more research is nec-essary to understand how to best inte-grate the methods.

The best method: Your eyes and hands

Conventional prevention efforts, such aspulling, cutting or digging the first plantsof an invasive species to appear in a newneighborhood, remain our primary (andcheapest) defense. New, small purpleloosestrife plants are easily pulled withall their roots intact, making this simple

operation extremely effective at prevent-ing new and larger infestations.

You are your neighborhood’s firstline of defense against increasing num-bers of invasive species. Educate your-self about local native flora, as well asestablished and new invasive plants, soyou can correctly identify an invaderand distinguish it from similar nativespecies, ideally even before flowers andseeds are produced. When you can rec-ognize new invaders, you can removethem in time to prevent seed from con-taminating a site for years to come.

Sensible prevention efforts shouldalso include careful scrutiny of anyplant before it is allowed into the coun-try; all new plant species should be ob-served in trial horticultural settings and

immediately eliminated if determinedto be invasive. Such a policy couldgreatly reduce the need for expensiveand laborious control programs.

Once a pest plant has established it-self on a site, the most efficient conven-tional control methods, such as herbi-cide use, are usually only cheap whenthe infestation is still relatively small.As the invasive plants spread, biocon-trol often becomes the only affordableand acceptable control option available.

Beetles put the bite on loosestrife

Almost 16 million new control beetlesare at work on purple loosestrife at over1,200 sites statewide, thanks to more

Volunteers raise young loosestrifeplants in pots covered with netting.Beetles used as biocontrols grow onthese nurse plants for several weeksthroughout the summer. More than500 volunteer groups have beentrained to raise and release beetlessince the program began in 1997.

Later in the growing seasonthe pots that are now full ofhungry beetles are placed in loosestrife stands andunwrapped so the beetles canspread into the stands andeat the invasive plants.

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10 Reasonable expectations

than 500 citizens and citizen groupswho took the time to rear and releasecontrol insects since 1997. Research atselected release sites has shown a sig-nificant reduction in loosestrife flower-ing, stem heights, number of stems andcover, along with increased mortality.With weakened loosestrife populations,native plants have regained a footholdat some sites. Declines in seed set havealso reduced loosestrife’s ability tospread to new sites. Ultimately, wehope biocontrol can supplant most con-ventional controls, but time will tell.

Understanding some of the reasonsfor the early success of this program canhelp us duplicate its results with otherinvasive plants. First, evolution pro-vided predator insects dependent onpurple loosestrife. Then, the Depart-ment of Natural Resources helped fundresearch in Europe and the U.S. thatfound the most likely control insects;tested them carefully; identified thefour safe, effective and hardy insectspecies we now use; and created sim-ple, backyard rearing procedures thatallow citizens with little ecological experience to easily multiply insect

numbers at home or school for releasein their local wetlands. The Departmentof Natural Resources also providedfunds and joined with the University of Wisconsin-Extension and other statepartners to educate citizens aboutloosestrife, explain biocontrols and pro-vide rearing materials.

There is still much biocontrol workto be done with purple loosestrife —and you can help! Control beetles havebeen released on only about 10 percentof Wisconsin’s loosestrife-infestedacreage, so plenty of opportunities re-main for citizens to help rear and re-lease beetles across the state. We alsoneed help with a road survey to findout how widespread loosestrife controlhas been to date. E-mail Brock Woods atbrock.woods@wisconsin.gov or call(608) 221-6349 to receive more informa-tion about helping.

Coupled with programs in otherstates to control plants of mutual concern, Wisconsin could apply the“loosestrife approach” to efficientlycheck the spread of other establishedinvasive plants. While biocontrol maynot work on all of them, prudence and

efficiency suggest funding additionalstudies on those plants that are the mostdamaging in the state. Until effectivebiocontrols are found for any particularspecies, it is very important to continueapplying all effective and safe conven-tional control methods, especially toprevent further spread.

Ultimately, both efforts will likely beneeded to keep a species in check. Someother invasive plants infesting Wiscon-sin and with known control insects in-clude Eurasian water-milfoil, spottedknapweed, leafy spurge, non-nativethistles and multiflora rose.

Eurasian water-milfoil is a sub-mersed aquatic plant that under theright growing conditions creates densemats in lakes, making recreational usedifficult and harming wildlife and fishpopulations. Several Eurasian water-milfoil herbivores have been investigat-ed as possible biocontrols. A nativeweevil has been shown to reduce theplant in some Wisconsin lakes. Effectivebiocontrol of this plant will requiremore funding for research since manyfactors may influence possible controlinsects. For example, we know thatmaintaining or restoring undevelopedshorelines allows larger populations ofthe native weevil to grow. On the otherhand, lakes with large bluegill popula-tions might not improve as much sincebluegills feed on these weevils. Devel-oping cheap, long-term biocontrols formilfoil-infested lakes will take time, sofunding the work now is critical for thelong-term health of our waters.

Leafy spurge, a deep-rooted perenni-al herb, forms large, dense patches andcan dominate mesic pastures, prairies,roadsides and other open areas. It reduces forage, can kill livestock andsignificantly reduces native plant popu-lations and wildlife. This invader has increased its spread and density on Wisconsin sites in the last several years.Six species of flightless Aphthona bee-tles have been imported from Europeand show some promise as controlagents, though they do not appear tomove very far on their own. Two speciesof Aphthona have been available in Wisconsin in late June for the last sev-eral years through the United StatesFish and Wildlife Service and the DNR.

Biocontrol projects still require hands-on, tiring work. Here clumps of loosestrife plants that were markedwith flags in spring and summer are dug out and removed in fall after the growing season. Loosestrifeplants are also used as host plants for raising beetles.

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E-mail Kelly Kearns at kelly.kearns@wisconsin.gov for in-formation.

Spotted knapweed, a hardyperennial herb, infests dry road-sides, prairies, pastures andfields, reducing their value forgrazing. It suppresses nativeplants, especially grasses,through allelopathy (producingcompounds that inhibit thegrowth of adjacent plants). Six-teen insect species have beenimported into the U.S. to con-trol knapweed. Two species ofUrophora flies are already es-tablished in Wisconsin and at work reducing knapweedseed production. More biocon-trol help is needed. It may comefrom a moth and several wee-vils being tested in the state.These insects show real promiseand may become available forgeneral use within severalyears. Contact Wade Oehmichenat wade.oehmichen@wisconsin.gov forspecifics on knapweed biocontrol.

Canada, musk, bull and other thistlesare all common Eurasian weeds that in-fest a range of habitats, degrade forage,and reduce crop values, as well as com-pete successfully with native plants. Avariety of insect species were importedto control these species with some goodresults. Unfortunately, one of them,Rhinocyllus conicus, established in thestate in 1978 before the current researchprotocols were in place and is now pro-hibited because it may also attack rarenative thistles. A native bacterial diseasehas shown some promise in decreasingthe vigor and flowering of Canada this-tle, but further study is needed.

Multiflora rose is another invasivethat may be controlled best with a dis-ease, rather than an insect. It is an Asianshrub that used to be planted to providewildlife habitat. Years of use reveal thatthis incredibly thorny hedge rose renderspastures unusable and reduces nativeplants on over 45 million acres in the U.S.A domestic search revealed a minutewasp, accidentally imported from Japan,and a European stem-girdling beetle mayhave some effect. A native viral disease,rose rosette disease, and a mite that

spreads this virus hold promise as con-trol agents. Although the virus can alsoaffect other rose species, it is fatal primar-ily to multiflora rose. This disease is pre-sent in southwestern Wisconsin and isspreading slowly by the mite and wind.Grafting an infected stem onto an unin-fected plant can introduce the disease tonew and established rose stands.

Native insects in other countries thatnaturally feed on garlic mustard, blackswallow-wort, buckthorn, commonreed grass and Japanese knotweed havebeen found. A biocontrol program forgarlic mustard is in the latter stages ofdevelopment, but few of the other in-sects have been tested. We need morefunding for research to learn if these po-tential controls can safely be madeavailable to contain these pest plants.

Garlic mustard, a Eurasian biennialherb, is a serious invader of forestedareas in Wisconsin, especially in thesouthern and eastern parts of the state.Massive stands frequently and drasti-cally crowd out native forest herbs andreduce forest productivity. Five weevilsand one flea beetle are being evaluatedas potential biocontrols. Two Ceu-torhynchus weevils are currently beingtested in quarantine in Minnesota and

may be available for experimental re-lease in 2008 or 2009 at Wisconsin re-search sites if deemed safe by a federaloversight committee.

It’s clear that insects and other natur-al disease controls hold promise forcontaining many of the troublesomeplants that are establishing themselveshere. If we’re lucky, some may do theirjob so well that ongoing human controlwork will no longer be necessary. Wis-consin must join other states in sup-porting the research to identify whichcontrol species are available, be surethey are safe and figure out how best toapply them in combination with con-ventional control methods. Lackingthese sensible and cheap approaches,we may well have to expend a lot moretime, effort and money in the struggleto check the advance of invasive plants— a struggle likely to last as long as we want to have healthy, functioningnative ecosystems.

Brock Woods is a research ecologist who alsoeducates and trains community volunteerswilling to undertake biocontrol programs tocontain invasive plant species. Mr. Woods hasa joint appointment with the Department of Natural Resources and the University ofWisconsin-Extension.

Part of the scientific work to document if we are making headway requires setting up sample transects, measuringplant densities of invasive species and noting changes over time.

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What could be more natural than an earthworm? As discussed in a previous story (“Worming into new territory,” Wisconsin Natural Resources, August 2005), at least since the last Ice Age earthwormshave not been part of the native mix of invertebrates that inhabited

the soils across the upper Midwest. While earthworms in farm country are prized foraerating and tilling farm and garden soils, that simply is not the case in the northernhardwood forests across Minnesota, Wisconsin and upper Michigan.

Normally in these forest soils, fungiand bacteria would more slowly de-compose leaf litter forming a light,spongy “duff” layer that allowsseedlings and understory plants togrow slowly. Earthworms in these samesoils digest both leaf litter and nutrientsmuch more quickly. Their castingsmake denser, claylike pellets of the lightsubsoil layers. Where earthworms gaina foothold, fewer soil nutrients areavailable, the soil becomes heavier,more compacted, and the understoryvegetation grows more sparsely, saysCindy M. Hale, research associate andenvironmental educator at the Univer-sity of Minnesota-Duluth. Her researchduring the last ten years shows that dif-ferent earthworm species live in differ-

last two years, other University of Min-nesota researchers examining beech for-est soils at Pictured Rocks NationalLakeshore in Michigan and aspen/spruce/fir soils at Voyageurs NationalPark in Minnesota found these differentforest types contain different mixes ofearthworm species. The maple forestsare twice as susceptible to earthwormdamage as the beech forests and fourtimes as susceptible as the spruce/aspen forests.

More recent studies suggest that

ent soil zones — some near the surfacein leaf litter, some in the top soil layers,and some burrow deep into the subsoil.Their combined actions can leave forestsoil less able to absorb water or supportplant life.

Forest types are not equally vulnera-ble to earthworm invasion or damage.Hale’s work shows that sugar mapleforests like those found in the ChippewaNational Forest in Minnesota and theChequamegon National Forest in Wis-consin, are more susceptible. During the

Invasion at a slow crawl

Invasion at a slow crawlDavid L. Sperling

Exotic earthworms are nosing into northern forests at an unnatural pace.

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Asian worm species of the genus Amynthus are brought into the U.S. because these “jumping” worm species are especially active on a hook. They are not native here and can do serious damage if they are released in forest soils or garden soils, or if they infiltrate landscape plant nurseries.

June 2007 13

earthworms found in northern foresthabitat can disrupt how tiny mycor-rhizal fungi interact with plant roots,slowing down the nutrient absorptionrate in fine root hairs. Other researchersare expanding these investigations ofearthworms in different kinds of forest-ed environments. DePaul University sci-entists are examining how earthwormdisturbance may open the way for inva-sive plants like buckthorn to expandtheir range once soil is disturbed. Den-nis Burton at the University of Pennsyl-vania is examining the pathways inwhich earthworms pave the way for ex-otic plant spread as native understoryplants die back. Projects at the Smith-sonian Institution are looking at mapleseedling changes, and at the Universityof Georgia in Athens, researchers arestudying how earthworm invasionsmay reduce food supplies available tojuvenile salamanders. At Cornell Uni-versity, scientists are investigating howthe combined effects of worm invasionand deer browsing can cause long termchanges to plant composition on the for-est floor.

Given that earthworm populationswould naturally spread their range atperhaps half a mile in 100 years, howhave these worm populations becomeso mobile? People. The 16 worm speciesand the dusky slug that now occuracross the Great Lakes region are mainlyEuropean species that were brought inaccidentally as worm egg cases hatchedfrom the soils in landscaping plants,trees, mulch and compost. Unused fish-ing worms cast aside near boat launch-es, landings and resorts establishedbeachheads to start new worm colonies.Mail-ordered worms for vermicompost-ing may inadvertently contain someeggs of other worm species. SeveralAsian species of the genus Amynthusare spreading along the East Coast andmoving westward. These species are es-pecially wiggly and active on a fishinghook and are being marketed as “jump-ing” worms. They can harm both foresthabitats and garden soils and haveraised serious problems for some plantnurseries.

How can you help stem the wigglinginvasion? Start by educating yourselvesand your gardening and fishing friends.

Websites, like the Great Lakes WormWatch, www.nrri.umn.edu/worms/provide background information to un-derstand earthworm behavior andidentify each species. The site also offers educationalmaterials like factsheets, posters andbrochures to ex-plain this issue to others. A newfield guide, Earth-worms of the GreatLakes Region, isalso available through their website.Worm Watch workshops that train vol-unteers to look for signs of earthworminvasions are offered periodicallythrough the Great Lakes Worm Watchwebsite. Workshops on worm identifi-cation and control have recently beensponsored at the University of Wiscon-sin-Stevens Point Learning, Experi-ences & Activities in Forestry (LEAF)program, www.uwsp.edu/cnr/leaf, andthe Beaver Creek Reserve (www.beavercreekreserve.org).

Second, take steps to avoid introduc-ing earthworms to new areas, especial-ly near forested areas. Dispose of un-used fishing bait in the trash. If you aremoving small amounts of compost

from one area to another and it is practi-cal, freeze compost for a week to kill offlive worms and worm egg casings be-fore you use it. For larger amounts,spread the compost thin and let it freeze

solid over winterbefore collecting itfor use elsewhere.Also don’t trans-port leaves, com-post or mulchlong distances toavoid spreadingworms from one

location to another. When plantingwildflowers, trees or shrubs into forest-ed areas, remove soil and rinse the rootsin a location away from the woods be-fore planting. And clean the dirt off ofATVs, motorcycles and other vehiclesthat might hold soil in their treads.

Finally, consider joining or starting alocal worm watch program, especially ifyou live in or travel to northern forestcountry where these worms are not partof the native mix of invertebrates. Again,the Great Lakes Worm Watch programcan suggest how to get going to slow thespread of these invasive species.

David L. Sperling edits Wisconsin NaturalResources magazine.

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Workshops train volunteers where and how to look for signs of worm damage in forested areas of thenorthern Midwest. Worms are more often found near the water’s edge on fishing lakes, near boat ramps,resorts and other areas people frequent.

14 Reasonable expectations

WHO: Boaters and Anglers

ACTION: Each time you get ready to leave a water body,make sure to:• Inspect your boat, trailer and equipment and

remove visible aquatic plants, animals and mud. • Drain water from your boat, motor, bilge, live

wells and bait containers.• Dispose of leftover bait in the trash, not in the

water or on the land.• Rinse your boat and recreational equipment

with hot water OR dry for at least five days.

WHO: Aquarium and Pond Owners

ACTION: Do not release any aquatic plants or animals intothe environment. If you have unwanted specimens,consider trading with another hobbyist, returningto the retailer or donating to a school. Make surethat your pond is constructed to withstand heavyrains — overflow can carry organisms from yourpond into nearby streams and lakes.

WHO: Campers

ACTION: Leave firewood at home and purchase firewood ator near your campsite location. Look for dry, agedwood that is less likely to contain pests.

Burn all wood during your trip — do not leave firewood behind and do not transport it to other locations. Also inspect clothing and equipment for mud and stowaways (seeds, insects, etc.) beforeleaving your camping area.

WHO: Hunters, Hikers, Bikers and Horseback Riders

ACTION: Seeds, eggs and other materials can be spread by the tread on your shoes and bike tires, on your clothes, and in your pets’ fur, hooves andmanure. Try to avoid walking through knownpopulations of invaders and check for mud andseeds before moving to a new area. Dispose ofany hitchhikers in a plastic bag in the trash.Horseback riders can feed their animals weed-freehay and feed for several days before venturinginto wild areas.

WHO: Gardeners

ACTION: Use native plant species whenever possible. Con-tact your local UW-Extension office to learn moreabout landscaping with natives. Get to know whichplants might be invasive and avoid planting themanywhere where they might spread.

WHO: Parents and Educators

ACTION: Teach kids about the environmental damage inva-sive species can cause. Get kids outside to appreciateWisconsin’s natural environment and involve themin education projects such as raising purple loose-strife biocontrol beetles. Contact DNR outdoor edu-cators to learn more about environmental educationopportunities, including Project WET, Project WILD,Project Learning Tree, and the Invaders of the Forestactivity guide.

WHO: Waterfront Property Owners

ACTION: Practice good lake stewardship — limit runoff, protect native plants, etc. — to keep your lakehealthy and resilient. Work with neighbors to educate lake residents and visitors about ways to limit the spread of existing invaders and avoidintroducing new aquatic invaders. Consider partic-ipating in Clean Boats, Clean Waters — Wisconsin’svolunteer watercraft inspection program. Monitoryour lake for invasives, and if any problem speciesare found, inform DNR lakes staff and work withthe agency on control options.

WHO: All Nature-Lovers

ACTION: Learn to recognize your local native plants and ani-mals. Then be on the lookout for invasive specieson your property and in the places you visit. Beginwork immediately to contain any new invaders —don’t wait until they get out of hand. Early detec-tion is often the key to controlling an invasion.

If you think you have spotted a new invader in yourarea, contact the DNR regional ecologist. When reporting an invasive species, collect a specimen ortake a photo and record details such as exactlywhere and when you found it.

Only YOU can stop the invasionEveryone who enjoys the natural treasures of Wisconsin can take steps to prevent the spread of

invasive species. Whether your passion is fish or flowers, your actions are a vital part of thestatewide campaign to control invasive species.

Julia Solomon

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Only YOU can stop the invasion

June 2007 15

INVASIVE SPECIES NATIVE AND NON-NATIVE ALTERNATIVESTREES/SHRUBSJapanese barberry False indigo (Amorpha fruticosa)

(Berberis thunbergil) American witch hazel (Hamamelis virginiana)

Boxwood ‘Glencoe’ or ‘Green Velvet’ (Buxus cultivars)*

Alpine currant (Ribes alpinum)*Spreading cotoneaster

(Cotoneaster divaricatus)*Winterberry holly (Ilex verticillata)Ninebark (Physocarpus opulifolius) Cutleaf stephanandra

(Stephanandra incisa)*Common buckthorn Speckled alder (Alnus incana)

(Rhamnus cathartica) American hazelnut (Corylus americana)Dwarf alder (Rhamnus alnifolia)

Glossy buckthorn Eastern arborvitae (Thuja occidentalis)(Rhamnus frangula ‘columnaris’) Gray dogwood (Cornus racemosa)

High-bush cranberry (Viburnum opulus subsp. trilobum)

Chokecherry (Prunus virginiana)Black chokeberry (Aronia melanocarpa)Eastern red cedar (Juniperus virginiana)Freeman maple

(Acer x freemanii ‘Armstrong’)Morrow honeysuckle Serviceberry

(Lonicera morrowii) (Amelanchier arborea, A. laevis,Tatarian honeysuckle A. spicata)

(Lonicera tatarica) Beautybush (Kolkwitzia amabilis)*Showy pink honeysuckle American elderberry

(Lonicera x bella) (Sambucus canadensis)Amur honeysuckle American red elderberry

(Lonicera maackii) (Sambucus pubens)Red honeysuckle (Lonicera dioica)Seven-son flower

(Heptacodium miconioides)*Swamp fly honeysuckle

(Lonicera oblongifolia)Autumn olive Rabbit-berry (Shepherdia canadensis)

(Elaeagnus umbellatus) Silverberry (Elaeagnus commutata)*Silky willow (Salix sericea)Red osier dogwood (Cornus sericea)Gray dogwood (Cornus racemosa)Silky dogwood (Cornus amomum)

Norway maple (Acer platanoides) Sugar maple (Acer saccharum)Red maple (Acer rubrum)Freeman maple

(Acer x freemanii ‘Armstrong’)*Miyabei maple (Acer miyabei)*Ginkgo (Ginkgo biloba)*Littleleaf linden (Tilia cordata)*

VINESOriental bittersweet American bittersweet

(Celastrus orbiculatus) (Celastrus scandens)Virgin’s bower (Clematis virginiana)Virginia creeper

(Parthenocissus quinquefolia) Trumpet vine (Campsis radicans)*American wisteria (Wisteria frutescens)*

INVASIVE SPECIES NATIVE AND NON-NATIVE ALTERNATIVESGROUND COVERCrown vetch (Coronilla varia) Whorled milkweed (Asclepias verticillata)Birds-foot trefoil (Lotus corniculatus) Spreading dogbane

(Apocynum androsaemifolium)Moss phlox (Phlox subulata)Canadian milk vetch

(Astragalus canadenis)American vetch (Vicia americana)Goat’s rue (Tephrosia virginiana)Common lupine (Lupinus perennis)Common tick trefoil

(Desmoium canadense)Cream wild indigo (Baptisia bracteata)

WILDFLOWERSDames rocket Garden phlox (Phlox paniculata)

(Hesperis matronalis) Carolina phlox (Phlox carolina)Wild bergamont (Monarda fistulosa)

Purple loosestrife Marsh blazing star (Liatris spicata)(Lythrum salicaria) Prairie blazing star (Liatris pycnostachya)

Dotted gayfeather (Liatris punctata)Wild bergamont (Monarda fistulosa)Joe-pye weed (Eupatorium maculatum)Purple coneflower (Echinacea purpurea)Queen-of-the-prairie (Filipendula rubra)Monkeyflower (Mimulus ringens)

Yellow iris (Iris pseudacorus) Blue flag iris (Iris versicolor)Marsh marigold (Caltha palustris)Cardinal flower (Lobelia cardinalis)

GRASSESMaiden grass (Miscanthus sinensis) Prairie cordgrass (Spartina pectinata)

Note — the ‘species’ is the invasive Indian grass (Sorghastrum nutans)form. Most ornamental cultivars Little bluestem (Schizachyrium scoparium)do not spread by seed, although Big bluestem (Andropogon gerardii)some could spread vegetatively. Prairie dropseed (Sporobolus heterolepis)

Reed canary grass Switchgrass (Panicum virgatum)(Phalaris arundinacea Prairie cordgrass (Spartina pectinata)includes variegated cultivar) Big bluestem (Andropogon gerardii)

Canada wild-rye (Elymus canadensis)Ice dance sedge (Carex morrowii)Autumn moor grass (Sesleria autumnalis)

AQUATICFlowering rush Common rush, Soft rush (Juncus effusus)

(Butomus umbellatus) Common threesquare (Schoenoplectus pungens)

Hardstem bulrush (Schoenoplectus acutus)River bulrush (Scirpus fluviatilis)

Water lettuce (Pistia stratiotes) Spatterdock (Nuphar variegata)Water hyacinth White water lily (Nymphaea odorata)

(Eichhornia crassipes) American lotus (Nelumbo lutea)Yellow floating heart Pickerel weed (Pontederia cordata)

(Nymphoides peltata) Water hyssop (Bacopa monnieri)Yellow pond lily (Nuphar microphylla)

* Not native to Wisconsin, but seem to be non-invasive.

We hope this helps add beauty to your garden. Happy planting!

Alternative plants for landscaping

There are hundreds of native and non-native alternatives to invasive species that look beautiful in your garden and do notpose a threat to the natural world. Non-invasive plants can offer stunning color, wildlife forage and interesting growthhabits. If you have some invasives in your yard, try replacing them with some of these non-invasive plants.

Sources: Midwest Invasive Plant Network, Landscape Alternatives for Invasive Plants of the MidwestAlternatives to Ohio’s Invasive Plant Species. www.oipc.info/ohioresources.html Burrell, Colston C., Brooklyn Botanic Garden All-Region Guides, Native Alternatives to Invasive Plants. Brooklyn Botanic Garden, Inc.Edited Abbey, Timothy M. Alternatives for Invasive Ornamental Plant species. Connecticut Invasive Plant Working Group. www.hort.uconn.edu/CIPWG/

16 Reasonable expectations

Keeping up to speedTo stay current on the latest information about known invasive species and spreading species under investigation, try thesewebsites and contacts:

INVASIVE PLANTS

dnr.wi.gov/invasives — Wisconsin Department of Natural Resources general invasives information. A good startingpoint to learn about invasive plants and animals with detailsabout programs to manage invasive species that affectforests, wildlife, parklands and aquatic environments. Thesite also has an excellent photo gallery of both invasive andnon-native plants.

dnr.wi.gov/invasives/futureplants/reporting.htm — Guidelines for reporting sightings of invasive species

dnr.wi.gov/invasives/pubs/ — Other resources and publications about invasive species

tncweeds.ucdavis.edu — The Nature Conservancy’s Wildland Weeds page

na.fs.fed.us/fhp/invasive_plants/index.shtm — The U.S. Forest Service website on invasive plants in our region

AQUATIC INVASIVE SPECIES

dnr.wi.gov/invasives/aquatic/ — DNR Aquatic InvasiveSpecies web page

www.dnr.wi.gov/invasives/aquatic/resrep.htm — DNR publications on aquatic invasive species

www.uwsp.edu/cnr/uwexlakes/ — UW-Extension Lakes Program website

seagrant.wisc.edu/ais/ — UW Sea Grant Aquatic InvasiveSpecies website

www.uwex.edu/erc/AquaInvHandbook.html — A Handbookfor Education Efforts on aquatic invasive species (downloadable)

ORGANIZATIONS

www.ipaw.org — The Invasive Plants Association of Wisconsin offers many services including a speakers bureau,educational resources and a wonderful list serve.

www.mipn.org — Midwest Invasive Plant Network

www.nps.gov/plants/alien — Plant Conservation Alliance’sworkgroup on alien plant invaders of natural areas

www.invasivespeciesinfo.gov — The National InvasiveSpecies Information Center

www.nrri.umn.edu/worms/ — Great Lakes Worm Watch

GENERAL PLANT IDENTIFICATION AND INFORMATION

www.botany.wisc.edu/wisflora — The Wisconsin StateHerbarium database and descriptions of Wisconsin vascularplants

wisplants.uwsp.edu — The UW-Stevens Point vascular plantdatabase

plants.usda.gov — U.S. Department of Agriculture plant database

www.inhs.uiuc.edu/~kenr/prairieplants.A.html — The Illinois Natural History Survey website contains macro photographs of seeds, fruits and flowers of native species.

RECOMMENDED BOOKS

Invasive Plants of the Upper Midwest, by Elizabeth Czarapata,2005, University of Wisconsin Press

Field Guide to the Invasive Plants of the Midwest, Midwest Invasive Plant Network

Pocket Naturalist Guide to the Invasive Plants of the Eastern United States, Waterford Press (available in fall 2007)

Earthworms of the Great Lakes Region, Great Lakes Worm Watch,Natural Resources Research Institute, 5013 Miller Trunk Highway, Duluth, MN 55811, (218) 720-4294

CONTACTS

Kelly Kearns, DNR plant conservation program manager, (608) 267-5066

Julia Solomon, DNR/UWEX aquatic invasive species educator,(608) 267-3531 (DNR); (608) 261-1092 (UWEX)

Brock Woods, Wisconsin purple loosestrife control coordinator,(608) 221-6349

Tom Boos, DNR forestry invasive plant specialist, (608) 266-9276

Jane Cummings-Carlson, DNR forest health coordinator, (608) 275- 3273

Ron Martin, DNR aquatic invasive species specialist, (608) 266-9270

Armund Bartz, DNR West Central regional ecologist, (608) 785-9019

Owen Boyle, DNR Southeast regional ecologist, (414) 263-8681

Joe Henry, DNR Northeast regional ecologist, (920) 662-5194

Ryan Magana, DNR Northern regional ecologist, (715) 635-4153

DNR South Central regional ecologist, (608) 275-3276

Mark Wetter, curator, Wisconsin State Herbarium, UW-Madison (608) 262-2792

Ted Cochrane, curator, Wisconsin State Herbarium, UW-Madison (608) 262-2792

Mark Renz, perennial systems weed ecologist, UW-MadisonDept. of Agronomy (608) 263-7437

Also consider contacting UW-Extension county horticulturalagents, county conservation departments, local offices of the Department of Natural Resources or the federal Natural Resources Conservation Service with questions about managing invasive species. © 2007, Wisconsin Department of Natural Resources Bureau of EndangeredResources, Publication ER-655-2007

Funding support from the Urban Horticulture – Wisconsin Program of the USDA CSREES, grant number 2006-45060-03702.

Opinions, findings, conclusions or recommendations expressed in this publication are those of the authors and do not necessarilyreflect the view of the U.S. Department of Agriculture.