Planting annual flowers to give pollinators a boost in yards and gardens

Dave Smitley, October 5, 2019Michigan State University

Recommending perennial flowers for bees and butterflies is easy!Lot’s of great choices listed in Extension publications

and many internet gardening sites

Herbaceous perennials attractive to beesCommon name (scientific name)

Anise hyssop Agastache foeniculumAromatic aster SymphyotrichumoblongifoliumAster Aster novae-angliae – ‘Purple Done’Astilbe, false spirea Astilbe spp.Basil, sweet basil (annual) Ocimum basilicumBee balm Monarda spp.Bellflower Campanula spp.Betony Stachys monieriBigleaf ligularia Ligularia dentateBlack-eyed Susan,coneflowerRudbeckia spp.Blanket flower GaillardiaBlazing star Liatris spicataButterfly bush Buddleja or Buddleia

Butterfly weed Asclepias tuberosaCalamint Calamintha nepetaCarolina lupine Thermopsis villosaCatmint Nepeta spp.Chrysanthemum(open types)ChrysanthemumAnise hyssop

Bee balm Monarda spp

From first page (A’s through C’s) of E3314 Update of‘Protecting Pollinators in Urban Landscapes’

But recommending annual flowers for pollinators is a little more difficult, especially for the most popular

annuals sold at garden centers

$1.5 Billion of Annual Flowers and $0.6 Billion of Perennial Flowers Are Sold in Garden Centers Each Year in the USA

(wholesale value)

But Most Consumers Do Not Know Which Ones are Attractive to Bee and Butterflies

Annuals Value in 2014 ($1000))Petunias 262,959

Geraniums (from vegetative cuttings) 223,954

Pansies (Violas) 186,024

Begonia 133,349

Impatiens, other (I. wallerana) 114,829

Impatiens, New Guinea 99,950

Marigold 82,362Combination planter/color bowl 81,344Geraniums (from seeds and plug seedlings) 46,657Calibrachoa 44,592Vinca (Catharanthus roseus) 42,236Coleus 19,900Zinnia 16,472Verbena 15,863Gerbera daisy 14,261Salvia, annual 13,977Fuchsia 13,805Caladium 12,639Dahlia 12,533Snapdragon 12,119Alyssum, sweet (Lobularia) 11,381Lobelia 11,259Portulaca 9,606Dianthus - tested as a perennial 7,736Celosia 7,614Pentas 7,377

The top 33 (in sales) account for 97% of the top 56

annual flower types sold

Annuals- what are they buying?

Annuals Value in 2014 ($1000)Petunias 262,959Geraniums (vegetative) 223,954Pansies (Violas) 186,024Begonia 133,349Impatiens (I. wallerana) 114,829Impatiens, New Guinea 99,950Marigold 82,362Combination/color bowl 81,344Geraniums (from seeds) 46,657Calibrachoa 44,592Vinca (Catharanthus) 42,236Coleus 19,900Zinnia 16,472Verbena 15,863Gerbera daisy 14,261Salvia, annual 13,977Fuchsia 13,805Caladium 12,639Dahlia 12,533Snapdragon 12,119Alyssum (Lobularia) 11,381Lobelia 11,259Portulaca 9,606

The Top Six Annuals are not very Attractive to Pollinators

( account for 67% of top 25 sales)

Which Annual

Flowers do People Buy?

About 80% are not very attractive to pollinators

Blue arrows indicate annuals attractive to pollinators

Bottom line: 75% or more of annuals sold are not attractive to

pollinators

What Happens if a Typical Homeowner Wants to Buy Annuals Attractive to Pollinators?

What Information is Available?

Example: E3314 Update of‘Protecting Pollinators in Urban Landscapes’

*A list of flower types, many of which are not available or have different names at their local garden center

Top 10 in USA salesTop 20 but not top 10

Alyssum (2)Anemone (1)Angelonia (6)Bachelor button (1)Bacopa (3)Biden (2)Browalllia (2)Caladium (1)Calibroachoa(24)Chrysanthemum (11)

Geranium (14)Hibiscus (7)Impatiens (27)Kalanchoe (7)Lantana (9)Mandevilla (6)Marigold (8)Mecardonia (1)Moss rose (4)

Snapdragon (1)Spider flower (2)Strawflower (2)Tulip (1)Verbena (14)Wishbone flower (3)Zinnia (6)

Nemesia (3)Penta plant (12)Periwinkle (4)Petunia (39)Phlox (1)Plectranthus(1)Purslane (6)Salvia (1)Scaevola (1)Sedum (2)

Coleus (9)Dahlia (3)Daisy (15)Dichondra (1)Dipladenia(3)Dracaena (1)Morning glory (1)Euphorbia (1)Fan flower (2)Gaura (1)

Annual Flowers Available at Home Depot: 46 types

Shop by ColorTHE HOME DEPOT

Reds and Pinks

Purples and lavender

Oranges and Peaches

Yellows and golds

Whites

Multi

What are they looking for?

Bright colors, easy to grow, something they are familiar with.

We Need to Provide Better Information to Greenhouse Growers (always looking for new flower products)

and ConsumersFirst: What does science know about annual flowers and

pollinators?

Also, it is important for growers to know which are attractive to pollinators so they can avoid using systemic insecticides on them!

1. Native flowers are not better than exotic flowers for honey bees, bumble bees and butterflies. But some native bee species have very specific food choices… so they are better for diversity.

2. Very few journal publications on the most popular annuals as food plants for bees and butterflies, but studies are under way.

“Protecting Pollinators with Economically Feasible and Environmentally Sound Ornamental Horticulture,”

is supported by a five-year SCRI grant funded for the first two years at almost $2.9 million. This funding will support 21 scientists and

extension experts at 12 different institutions

• James Bethke (University of California-ANR)• Lea Corkidi, Leah Taylor

• Christine Casey (University of California-Davis)• JC Chong (Clemson University)• Rich Cowles (Connecticut Agricultural

Experiment Station)• Brian Eitzer (Connecticut Agricultural

Experiment Station)• Dan Gilrein (Cornell Cooperative Extension of

Suffolk County)• Christina Grozinger (Penn State University)

• Emily Erickson, Doug Sponsler

• Zachary Huang (Michigan State University)• Hayk Khachatryan (University of Florida)• Elena Nino (University of California-Davis)• Cristi Palmer (IR-4, Rutgers University)

• Amy Abate, Dave Bodine, Tom Freiberger, Yu-Han Lan

• Harland Patch (Penn State University)• Dan Potter (University of Kentucky)

• Adam Baker, Bernadette Mach, Carl Redmond

• Dave Smitley (Michigan State University)• Erika Hotchkiss, Colin O’Neal

• Kimberly Stoner (Connecticut Agricultural Experiment Station)

• Nishanth Tharayil (Clemson University)

• Project leader: Cristi Palmer (Director of Ornamenatal Horticlutre for IR-4)

Stakeholder Advisory Group• Jennifer Browning, BASF• Joe Chamberlin, Valent Corporation• Harvey Cotten, Horticulture Research

Institute• Stephanie Darnell, Bayer Environ.

Science• Dave Fischer, Bayer Environmental

Science• Rufus Isaacs, Michigan State University• Gary Mangum, Owner, Bell Nurseries• Terril Nell, American Floral

Endowment• Randy Oliver, Scientific Beekeeping• Ed Overdevest, Owner, Overdevest

Nurseries

• Jay Overmyer, Syngenta Crop Protection

• Casey Sclar, American Public Gardens Association

• Becky Sisco, IR-4 Western Region• Tim Tucker, Amer. Beekeeping

Federation• Mark Yelanich, Metrolina

Greenhouses, Inc.• Vickie Wojcik, Pollinator Partnership• Ex officio: Tom Moriarty, Tom Steeger,

EPA

Protecting Pollinators Requires a Multistep Process

• Pollinator Attractiveness of Ornamental Horticulture Crops

• Risk Assessment Data Gaps• Economic, Efficacy, and Toxicological

Comparisons of Alternatives• Public Perception of Management Practices

& Point-of-Purchase Display Materials• Development of New BMPs• Outreach

-Evaluate Pollinator Attractiveness-also determining residue of systemic insecticides in nectar and pollen

2017 MSU Pollinator Attractiveness Plots for Annuals.

2016 PSU Pollinator Attractiveness Plots for Annuals. Photo by Nick Sloff.

During 2017, scientists in six locations throughout the United States are studying the top 20 to 25 annuals and perennials grown in the US. They are counting the number of each pollinator group visiting of 3 to 5 cultivars of each plant species.

Researchers: Drs. Jim Bethke, Christine Casey, JC Chong, Christina Grozinger*, Harland Patch*, Dan Potter, Dave Smitley, Kim Stoner*

States: CA, CT, KY, MI, PA

SCRI grant major objectives are:

Annuals Value in 2014 ($)Petunias 262,959Geraniums (from vegetative cuttings) 223,954Pansies (Violas) 186,024Begonia 133,349Impatiens, other (I. wallerana) 114,829Impatiens, New Guinea 99,950Marigold 82,362Combination planter/color bowl 81,344Geraniums (from seeds and plug seedling 46,657Calibrachoa 44,592Vinca (Catharanthus roseus) 42,236Coleus 19,900Zinnia 16,472Verbena 15,863Gerbera daisy 14,261Salvia, annual 13,977Fuchsia 13,805Caladium 12,639Dahlia 12,533Snapdragon 12,119Alyssum, sweet (Lobularia) 11,381Lobelia 11,259Portulaca 9,606Dianthus - tested a perennial 7,736Celosia 7,614Pentas 7,377Osteospermum 6,322Angelonia 5,633Dusty miller s 4,238Flowering cabbage or kale (Brassica) 3,620Scaevola 3,570Ageratum 3,126Ranunculus 2,140Gazania 2,082Millet, ornamental 2,013Canna 1,656Rudbeckia 1,433Thunbergia (Black-eyed Susan vine) 1,338Cosmos 1,230Peppers, ornamental 1,166Gomphrena 867Cleome 858Nicotiana 724Calendula 555Nasturtium 413Lisianthus 334Poppy (annual) 291

Perennials lue in 2014 Chrysanthemums (hardy/garden) 202,575Hostas 58,375Daylilies 28,517Ferns (hardy/garden) 20,389Salvia (perennial) 16,695Dianthus 15,170Coral bells (Heuchera) 15,149Sedum 15,031Coreopsis 14,038Lavender 13,748Phlox 12,880Echinacea (Purple coneflower) 9,691Rudbeckia 9,501Peonies 9,157Astilbe 8,005Leucanthemum (Shasta Daisy) 6,754Delphinium (Larkspur) 5,967Echinacea (other) 5,966Hibiscus 5,574Iris 5,212Columbine 4,667Gaillardia 4,325Veronica 4,063Digitalis (Foxglove) 4,044Perovskia (Russian Sage) 3,809Achillea 3,308Bleeding heart 3,267Penstemon 3,212Clematis (non-climbing) 2,543Asclepias 2,324Campanula 2,259Papaver (Poppy) 1,827Lupine 1,692Lobelia 1,268Scabiosa 1,170Platycodon 839Verbascum 476Physostegia 293

Evaluation of Top Selling Annuals and

Perennials in the USA in 2014

(NASS Survey)

The top 33 account for 97% of sales of the top 56 annual flower types sold

Pollinator Attractiveness of Top Selling Annual FlowersAt MSU- 26 cultivars, six replications, repeated for two years

CULTIVAR EVALUATION OF THE SIX MOST POPULAR ANNUAL FLOWERS AND FIVE OF THE MOST POPULAR PERENNIAL

FLOWERS SOLD AT GARDEN CENTERS, FOR THEIR ATTRACTIVENESS TO POLLINATORS

ByColin O’Neil (MS student)

Erica Hotchkiss (technician)Dave Smitley (PI)

Results compiled by Colin O’neil

Annuals Results 2017

All Cultivars(No Statistical Comparisons!)

Standard Results 2017

Zinnia Marigold

Polli

nato

r Visi

ts P

er S

ampl

e Pe

riod

0.25

1.0

Annuals Results 2017

Apis mellifera

Geranium Pansy Begonia Impatiens Petunia NG Impatiens

0.01

0.02 None of the annuals were very attractive to honey bees (1/4 or less than marigold)

0.05 (4X more than geranium)

Marigold

Annuals Results 2017Bombus

impatiens

Geranium Pansy Begonia Impatiens Petunia NG Impatiens

Geranium flowers were fairly attractive to bumble bees, with variation among cultivars

0.06

0.02

Annuals Results 2018

All Cultivars(No Statistical Comparisons!)

Chrysanthemum Results 2018

ApisBombusOther DipteraFlower flies

Cultivars of mums

• Variation Among Cultivars is Not New• Lavandula (lavender) and Dahlia cultivars can

outperform each other by a factor of over 10

Garbuzov and Ratnieks (2014)

Conclusions from Top Annuals Study

• Most of the top five are not very attractive to pollinators• Some geranium cultivars are attractive to bumble bees• Begonia can be attractive to flower flies• Some cultivars of chrysanthemums are very good in fall for

pollinators (frost tolerant)• Lots of variation among cultivars• More data needed for butterflies

Future recommendations need to be:• Specific for honey bees, bumble

bees, native bees or butterflies• Cultivar specific

Where Does This Leave Us for Recommending Garden Center Flowers for Homeowners?

• Plant as many pollinator-friendly trees and shrubs as possible• Choose pollinator-friendly perennials and herbs as much as possible • For top-20 annuals: Marigold (Tagetes), Moss rose (Portulaca), Salvia, Snap

dragon (Antirrhinum), Sweet alyssum (Lobularia), Zinnia• For other top 20-50 annuals: Biden, Chrysanthemum, Dahlia, Gaura, Penta,

Wishbone flower (Torenia)• Check with garden centers in area to see who carries, sunflowers (or plant

seeds), other Helianthus, Star flower (Borage) or other super-attractive but hard to find annuals.

• Watch for new publications with cultivar recommendations! (critical)

• Watch for new publications that give specifics on honey bees, bumble bees, native bees and butterflies.

Mach BM, Potter DA (2018) Quantifying bee assemblages and attractiveness of flowering woody landscape plants for urban pollinator conservation. PLoS ONE 13(12): e0208428. https://doi.org/10.1371/journal.pone.0208428

Mihail Garbuzov* and Francis L. W. Ratnieks. 2014. Quantifying variation among garden plants in attractiveness to bees and other flower-visiting insects.Functional Ecology 28, 364–374.

Rosi Rollings and Dave Goulson. 2019. Quantifying the attractiveness of garden flowers for pollinators. J Insect Conserv (2019). https://doi.org/10.1007/s10841-019-00177-3

Some Excellent Journal Publications:

Lavender!

Rollings and Goulson 2019

Plant cultivar Honey bee/m2

Bumblebees/m2

Solitary bee/m2

Total bees/m2

Lepidoptera/m2

hoverfly/m2

Other pollinator/m2

Total pollinators/m2

Rank

Calaminthanepeta

82.3 22.1 5.3 109.7 2.2 0.2 0.4 112.5 1

Helenium autumnale

83.0 2.4 12.0 97.4 0.0 1.9 0.6 99.9 2

Geranium rozanne

55.0 6.0 29.0 90.0 2.0 0.0 0.0 92.0 3

Helenium“Sahin’s early flowerer”

68.1 8.3 4.5 80.9 0.4 2.9 0.2 84.4 4

Rollings and Goulson 2019Evaluated and ranked 111 perennial and annual

garden plants

Rank(1 to 111)

Annual flower* Native to UK

5 Borago officinalis (spring sown) No

23 Echium vulgare “blue bedder” Yes

29 Calendula officinalis No

38 Phacelia tanacetifolia (autumn sown) No

41 Phacelia tanacetifolia (spring grown) No

44 Salvia viridis No

54 Cosmos bipinnatus No

55 Borago officinalis (over–wintered) No

56 Dahlia No

Rollings and Goulson 2019Rankings of best annuals for pollinators in list of 111 garden plants

(based on total of all pollinators, honey bees the most abundant)

* All of the above flowers would be included in our list of ‘annuals attractive to pollinators’ if they were available

Much Thanks for the Support of:

Michigan AgBioResearchAmerican Floral EndowmentHorticultural Research InstituteUSDA NIFA IR4Michigan Pollinator Initiative