Invasive Species of Iowa

Common Carp at Lake Meyer

Iowa’s Most Costly Invasive Species

Another Agricultural Pest

Headed in our Direction

An Emerald Menace

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Native lady beetles are never a nuisance and hibernate under decayed tree bark out in the woods. They don’t bite or stink.

All ladybird beetle larvae are beneficial. They eat aphids and scale insects and other bugs that cause gardeners headaches.

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Another Pest headed for the Midwest…

Another Emerald Menace

Another Familiar Pest

Pigeons and Doves

Managing Invasive Animals

• Don’t release domestic or non-native animals into the wild

•Stop aquatic hitchhikers

•Don’t transport or purchase non-local firewood

•Stay informed

Invasive Plants in Open Areas

Bull Thistles can be a big prickly problem

Bull Thistles can grow six feet tall and flower abundantly in late August

Musk Thistles look a lot like Bull Thistles, growing just as tall.

Musk Thistles have purple flowers that bloom in mid-July. Note the spiny collar at the base of that blossom.

Canada Thistles are the smallest thistle plants around here, but they present the biggest control challenge.

Canada Thistles normally grow about knee high. Unlike other thistles that spread via seed, Canada Thistles primarily spread from their roots.

Canada Thistles can create huge colonies that produce enormous amounts of seeds in late July.

Common Teasel

Dame’s Rocket, aka Phlox

Bifid Hemp Nettle

Wild Parsnip is another big problem plant in Iowa. Growing head high, yellow flower umbels form in late June.

Wild Parsnip plants are abundant in area ditches and old fields, and can hurt people a lot worse than thistles.

If your skin touches a Wild Parsnip plant when the sun’s shining, you’re almost certain to get a chemical burn.

Even small first year plants can burn you, but you can also eat them.

Wild Parsnip

Tansy

Leafy Spurge

White Sweet Clover has white flowers and is common in road ditches too. It is one of several invasive legumes in open areas.

Yellow Sweet Clover doesn’t spread quite as fast as it’s white cousin, but watch it anyway.

Crown Vetch is another invasive legume plant common in grassy areas

Crown Vetch leaves are somewhat pea-like.

Crown Vetch flowers are actually quite attractive and were widely planted as a roadside landscape plant years ago.

Crown Vetch populations exploded into surrounding areas after colonization.

Birdsfoot Trefoil

Reed Canary Grass is another problem plant in wet areas. This is a tall grass, growing up to seven feet.

Reed Canary Grass spreads by rhizomes and forms very large dense colonies, killing off the competition.

Reed Canary Grass blooms in early July.

Most wildlife avoids the difficult mats of Reed Canary Grass, but this hungry spider found a home on one plant.

Monocultures, like this Reed Canary Grass stand, are never a good thing in nature as they suppress diversity.

Smooth Brome

Chinese Silver Grass, Miscanthus sinensis

Other Non-native Grasses

Cool Season Pasture Grasses: quack grass, orchard grass, timothy, tall fescue and meadow fescue

Dry land grass:western cheat grass

Wet, acidic soils:Japanese stilt grass

Invasive Species in Wetlands

Invasive Species in Woodlands

Garlic Mustard may be the nastiest alien in our woods today

Garlic Mustard plants in year one have scalloped round leaves in a basal rosette.

Second-year Garlic Mustard plants bolt and form white flowers in late May.

Garlic Mustard was brought to this country as a garden vegetable, but it escaped to take over the woods. Enjoy!

Multiflora Rose was brought to this country on purpose too, planted as a pretty living barbed-wire fence.

Multiflora Rose leaves look like any regular rose.

Multiflora Roses are snow white, blooming in June.

Multiflora Rose hips are scarlet red and decorate the plants by late summer.

Hungry songbirds freely spread their seeds.

Multiflora Rose makes an impenetrable tangle in infested timbers

Japanese Barberry is another thorny woodland invader.

Japanese Barberry has small roundish clasping leaves and forms oblong fruits.

Japanese Barberry berries turn red as Rudolph’s nose in autumn.

Burning Bush

A Japanese Barberry jungle.

Japanese Bamboo is incredibly invasive and almost impossible to eradicate.

Japanese Bamboo was brought here as a novel hedge plant, but it quickly grew out of control.

Japanese Bamboo has distinctive red stems. The plant spreads by underground roots or even detached plant parts.

Japanese Bamboo flowers in midsummer

Stinging Nettle, otherwise known as Burning Weed, can form extensive patches in open woodlands.

Stinging Nettle leaves contain calcium oxalate crystals that burn when they penetrate our skin surface

Autumn and Russian Olive

Tartarian Honeysuckle is a real aggressive shrub all across the Midwest.

Like a broken record, Honeysuckle was brought here on purpose, planted for it’s pretty fragrant flowers, blooming in May.

By midsummer, red or orange translucent fruits are forming. These berries are too insipid for people, but birds eat them.

Native Honeysuckle – Lonicera dioica

Spread by birds, Honeysuckle shrubs sprout almost anywhere and shade out surrounding plants.

This woodland understory is totally overgrown with Honeysuckle, showing up as the green growth in spring.

Honeysuckle can cause problems out in open areas too, taking over fencelines and even fallow grasslands

Spring wildflowers like Bloodroot will be smothered out by these screening Honeysuckle shrubs

Honeysuckle sprouts multiple stems, making control difficult

This area has just been cleared of Honeysuckle bushes

European Buckthorn can grow as either a shrub or small tree out in the woods.

Buckthorn was brought from Europe as a yard hedge and landscape plant, but took off in our timbers.

Identify European Buckthorn by scraping back the bark, exposing the orange interior.

European Buckthorn is not called a “thorn” for nothing. Stems end in a sharp spine.

European Buckthorn leaves often look glossy. They leaf out before native trees in spring and stay green late into fall.

European Buckthorns produce purple berries in autumn. Birds eat them, get sick and expel them into new areas.

Amur Maple

More Invasive Species in our Area

Iowa DNR

Minnesota DNR

Wisconsin DNR

Ridding our woods and fields of non-native weeds is time-consuming and expensive

Tordon is a cheap reliable tree killer.

Coat the living tissue of a cut stump with Tordon RTU

A simple girdle, followed by squirting Tordon into the cut, will also kill Buckthorn or other weed trees.

Girdles can also be done with a few simple hatchet chops.

Trees with minimal wildlife value are eliminated from natural areas in autumn and winter by girdling and then treating the wound with Tordon.

A hop hornbeam, or ironwood tree that has been girdled and then treated with Tordon. These common trees shade the forest floor and prevent oak seedlings from getting established.

A hatchet-girdled tree trunk waiting for the Tordon spray

A tree loppers can be used to top smaller trees and honeysuckle shrubs

Honeysuckles can be a bear to cut

Be sure to give all lopper-cut stems the Tordon treatment.

A backpack sprayer works great for many noxious weeds

Hit Honeysuckle or other weeds in the summertime with Crossbow. Spray the vegetation until leaves are wet

Reed Canarygrass can be controlled with Select, which will kill any grass but won’t hurt sedges or forbs (flowers).

Backpack sprayers can get to hard-to-reach locations

Mowing can suppress weeds and keep them from going to seed. This may eventually control biennial species.

Fire may be another non-chemical control agent for weeds, but is better at battling a woody shrub or tree invasion

A late fall or early spring woodland burn can kill seedling Buckthorn, Honeysuckle and other ilk.

Hop hornbeam saplings waiting to be killed at Lake Meyer so the forest there can regenerate young oak or sugar maple seedlings in their place.

South-facing slopes at Lake Meyer are dominated by picturesque old oaks and managed as oak savannah, one of the rarest habitats in the whole world, a holdover from prehistoric times.

A natural native habitat is a healthy habitat