Bumble Bee Flower Finder

Flowers for Bumble Bees

The Bumble Bee Flower Finder helps you discover and grow native plants for bumble bees from the Eastern United States. Find flowers or get plans for wildlife gardening, ecological landscaping, and bee watching. Under construction. info@bumblebeeflowerfinder.info

Find flowers (✿) for places (☼) or plan plantings (♣) with perks (+). Match and mix selections and inputs. Fields are required for plans. Click the "Find" button for galleries or the "Plan" button for plans. Reload to reset. Help bumble bees find more flowers.

✿ Bloom February March April May June July August September October November Spring Summer Fall Winter

✿ Color Gray White Red Orange Yellow Cream Green Blue Lavender Violet Purple Magenta Mauve Rose Pink Brown

✿ Height ' –

✿ Form Arching Basal Clumping Branching Climbing Ephemeral Mounding Oval Rosette Round Sprawling Thicket Trailing Twining Upright Vine

✿ Growth Hemiparasitic Highly Persistent Long-Lived Persistent Seeding Short-Lived Slow Spreading

✿ Cycle Annual Biennial Deciduous Evergreen Perennial Shrub Subshrub Tree

☼ Light Sun (≥ 6 hrs) Part (≥ 3–6 hrs) Shade (≤ 3–6 hrs)

☼ Water Dry Moist Wet Aquatic

☼ Soil Acid Alkaline Clay Fertile Gravel Loam Muck Salt Sand Silt Sterile

☼ Zone 2 3 4 5 6 7 8 9 10 11

☼ Ecoregion 5. Northern Forests 6. Northwestern Forested Mountains 7. Marine West Coast Forests 8. Eastern Temperate Forests 9. Great Plains 10. North American Deserts 11. Mediterranean California 12. Southern Semi-Arid Highlands 13. Temperate Sierras 15. Tropical Humid Forests

☼ State CT DE KY MA MD ME NH NJ NY PA RI VA VT WV

♣ Habitat Banks Bluffs Clearings Ditches Fields Forests Glades Lawns Marshes Meadows Pastures Roadsides Shores Swamps Thickets Woodlands

♣ Feature Insectary Wildflower Shrubland

♣ Grade Flat Gentle Steep

♣ Cover Weak Strong

♣ Length '

♣ Width '

＋ Benefit Biocontrol Birds Butterflies Carbon Sequestration Compaction Cut Flowers Dye Erosion Control Food Honey Mammals Medicine Phytoremediation Preserves Specialist Bees Tea Tools

＋ Bombus Queens Workers Males

＋ Keyword

Find Plan

Bumble Bees

Bumble bees are charismatic social insects and valuable wild pollinators. There are around 260 species of Bombus (Phylum Arthropoda: Subphylum Hexapoda: Class Insecta: Order Hymenoptera: Family Apidae: Subfamily Apinae: Tribe Bombini) worldwide and 46 north of Mexico. Seven subgenera and 21 species of bumble bees are native to the Eastern United States.

Click Here to Identify Bumble Bees

Bombus are most diverse in temperate biomes with continuous supplies of pollen and nectar. Female bumble bees are pollen generalists (polyleges) who can buzz flowers to extract pollen and gather grains in pollen baskets (corbiculae) on hindlegs for transport. Both males and social parasite cuckoo bumble bees feed on floral rewards, but neither have corbiculae nor provision nests.

A queen bumble bee awakes from winter diapause, forages flowers, and founds a nest. Worker daughters eclose during spring, tend the family, and forage to help mom stay at home. [Cuckoo queens usurp established nests.] Males and virgin queens (gynes) mature from summer to fall, feed, and mate. Queens, workers, and sons die during autumn. Mated gynes overwinter and repeat the annual colony cycle.

Over 35% of regional bumble bees are endangered, threatened, vulnerable, or data deficient. Bombus affinis and cuckoo variabilis are critically endangered, fraternus is endangered, terricola, fervidus, and pensylvanicus are vulnerable, while cuckoo ashtoni and others are threatened or data deficient. You can support bumble bees by planting a selection of preferred flowers.

Methods

Bumble bee descriptions and records were compiled from books, peer reviewed articles, personal communications, technical bulletins, and websites. Illustrations by Elaine Evans and The Xerces Society. Plant descriptions were compiled from books, manuals, observations, and websites. Plant images are from Wildflower Search. Plant distributions are from The Biota of North America Program.

The Flower Finder includes native plants for bumble bees indigenous to at least one county of one of 14 states: Connecticut, Delaware, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, and West Virginia. Widespread plants with surplus floral rewards who also host native pollen specialist bees were prioritized.

Seven ratings (*****–0) were graded for each plant species: queens, workers, males, nectar, pollen, pollen specialists, and nursery availability. Blooms and Bombus caste phenologies were correlated, surplus pounds were estimated, specialist bee species were summed, and nursery availability was ranked. Grades were curved and averaged to calculate one overall rating for each plant species.

The Planting Planner designs with top rated bumble bee flowers. Continuous blooms and common availabilities are prioritized. Insectary = Annuals + Biennials + Short-Lived Perennials; Wildflower = Biennials + Perennials; Shrubland = Perennials + Shrubs + Trees. Select options to create plantings that bring benefits, host bees, and meet aesthetic needs.

Synopsis

Fifty-five families, 50 subfamilies, 61 tribes, 145 genera, and 272 species of native plants are catalogued. The most listed family is Asteraceae, subfamily is Asteroideae, tribe is Astereae, and genera are Solidago, Helianthus, and Symphyotrichum. Flowers are often white, pink, or yellow; racemes, panicles, or clusters; lobed, fragrant, or tubular; Blooms are most bountiful during June, July, or August.

Top rated bumble bee flower genera are Asclepias, Cirsium, Helianthus, Monarda, Pycnanthemum, Solidago, and Symphyotrichum. Top rated nectar plants include Liriodendron, Phacelia, Rhus, Robinia, Scrophularia, and Tilia. Both top rated pollen plants and hosts for pollen specialist bees are Solidago, Helianthus, and Symphyotrichum.

Pollen grains are commonly yellow, round, or spiny. Fruits are frequently cypselae, capsules, or pods. Roots are regularly rhizomes, fibrous, or taproots. Leaves are oftentimes toothed, hairy, or lance-shaped. Stems are mostly alternate, hairy, or square. Forms are frequently upright, branching, or basal. Growth is generally by seeding or spreading. Cycles are often perennials, shrubs, or trees.

Plants are often 1–3', 2–4', or 3–6' tall and 1–2', 2–3', or 1–3' wide. Light needs are commonly sun (≥ 6 hrs) or part shade (≥ 3–6 hrs), but rarely part sun–shade (≤ 3–6 hrs). Water needs are normally dry–moist, moist, or moist–wet. Soil needs are often well-drained, fertile, sand, or gravel. Zones are usually 6, 7, or 5 in ranges 3–8, 3–9, or 4–9. Habitats occupied are often woodlands, roadsides, or thickets.

Ecoregions inhabited are habitually Eastern Temperate Forests, Northern Forests, or Great Plains. States inhabited are mostly NY, PA, or NJ, while states uninhabited are mainly ME, VT, or NH. Benefits are chiefly medicines, birds, or mammals. Detriments are regularly rare or historic ranges, or normally none. Propagation methods are commonly sowing, dividing, or cutting.

Recommendations

The Bumble Bee Flower Finder can help you: discover the best native plants for plantings; identify bumble bees and flowers; determine plant materials needed for landscape designs; restore bumble bee habitats; and enhance farmscape health while ensuring crop pollination. Bumble bee flowers are often keystone species who support ecosystems, regulate detriments, and provide benefits.

Bumble bee queens need both late fall and early spring floral rewards to survive before and after winter diapause. If queens are well-fed with abundant, connected, continuous, and diverse supplies of pollen and nectar, then bumble bee families can grow healthy and large. Bigger plantings (≥ 3,600 square feet) host more diverse populations of bumble bees than smaller plantings (≤ 360 square feet).

Bumble bee foraging distances are normally less than half of a mile from nests. Grow plantings at ≤ 0.5 mile intervals to connect bumble bee habitats. Networks of bumble bee gardens can counteract species declines while expanding environmental awareness and education. We can help bumble bees by planting native bumble bee flowers. https://bumblebeeflowerfinder.info.

Disclaimer

Please: know your ecosystems, targeted species, poisonous lookalikes, and follow local laws before harvesting any wild plants at your own risk; Monitor and steward all harvested habitats. Horticulture requires training and practice. Guard yourself from injury by knowing your physical limitations, wearing protective gear, and wielding clean and sharp tools while working.

Acknowledgments

Produced by Jarrod Fowler (2022). Engineered by James Edwards. Supported by Ask A Bumble Bee, The United States Geological Survey Native Bee Inventory and Monitoring Program, The United States Fish and Wildlife Service, and The Polistes Foundation. Images from Wildflower Search (Authors, Contributors, & Sources). Illustrations by Elaine Evans and The Xerces Society. Rusty Patched Bumble Bee illustration by Pollinator Partnership. Native American Ethnobotany from indigenous peoples: Abenaki, Accomack, Adena, Akimel, Alibamu, Apache, Appamattuck, Apsáalooke, Arosaguntacook, Arrohatec, Ashiwi, Atsugewi, Aucocisco, Baaja, Calicuas, Chahta, Chalá·at, Chatiks, Chehalis, Cheroenhaka, Chesapeake, Cheyenne, Chickahominy, Chikashsha Yaki, Choctaw, Chowanoke, Corchaug, Coushatta, Cuttatawomen, Dakota, Diné, Ditidaht, Doeg, Eastern Nehântick, Erie, Hammonassets, Haudenosaunee, Havasupai, Havsuwʼ, Ho-de-no-sau-nee-ga, Hoocągra, Hopewell, Hopi, Houma, Hualapai, Inuit, Isleta, Iswä, Jemez, Ka'igwu, Kānaka, Kanienʼkehá꞉ka, Karuk, Kaskaskia, Kauwets'a:ka, Kecoughtan, Keres, Kiskiack, Klamath, Kumeyaay, Kwakwa̱ka̱ʼwakw, Laguna, Lakota, Lekawe, Lenape, Lənape Haki-nk, Lumbee, Mahuna, Maidu, Manahoac, Manissean, Mannansett, Maoli, Massa-adchu-es-et, Massacoes, Massawomeck, Matinecock, Mattaponi, Meherrin, Menominee, Merrick, Meskwaki, Mi'kmaq, Mississauga, Miwok, Mohave, Mohegan, Mohican, Monacan, Moneton, Moraughtacund, Munsee Lenape, Muscogee, Myaamia, Numunuu, Nacotchtank, Nahaganset, Nandtaughtacund, Nansemond, Narantsouak, Natchez, Nauset, Néhinaw, Nentego, Neshnabé, Newe, Niitsitapi, Nipmuc, Nisenan, Nissaquogue, Nlaka'pamux, Nottoway, Nuciu, Nuwa, Nuxalk, O-ga-xpa Ma-zhoⁿ, O'odham, Occaneechi, Occohannock, Očhéthi, Očhéthi Šakówiŋ, Odǫhwęja:deˀ, Oglala, Ohlone, Ojibwe, Omaha, Onawmanient, Onöndowa'ga:', Onundagaonoga, Onʌyote'a•ka, Opiscopank, Osage, Paiute, Pamunkey, Paspahegh, Passamaquoddy, Paugussett, Pawtucket, Payómkawichum, Pennacook, Penobscot, Pentucket, Pequawket, Pequot, Piscataway, Pocomoke, Pocumtuc, Podunks, Pokanoket, Pomo, Ponca, Poteskeet, Powhatan, Pueblo, Quechan, Quileute, Quinnipiac, Quiyoughcohannock, Rappahannock, S’atsoyaha, Saanich, Šakówiŋ, Sanpoil, Saponi, Saura, Secatogue, Secwépemc, Séliš, Setalcott, Shawandasse Tula, Shinnecock, Shoshone, Sqeliz, Susquehannock, Syilx, Tanana Athabaskans, Tlingit, Tohono O'odham, Tsalagi, Tübatulabal, Tunxis, Tuscarora, Tutelo, Unkechaug, Wabanaki, Wailaki, Wangunks, Wappinger, Warraskoyack, Wašišiw, Wenrohronon, Werowocomoco, Weyanock, Wicocomico, WiYaPeMiAk, Wôpanâak, Yat'siminoli, Yavapai, Youghtanund, Yuki, Zuni, ʔívil̃uqaletem, ᏣᎳᎫᏪᏘᏱ Tsalaguwetiyi ...

References

• Alford, D.V. (1969). A study of the hibernation of bumble bees (Hymenoptera: Bombidae) in southern England. Journal of Animal Ecology, 38: 149–170.
• Alford, D.V. (1974). Bumblebees. Davis-Poynter.
• Ascher, J.S. & Pickering, J. (2022). Discover Life Bombus Identification Guide. https://www.discoverlife.org/mp/20q?guide=Bombus.
• Baker, H.G. & Baker, I. (1983). Floral nectar sugar and constituents in relation to pollinator type. In C.E. Jones and R.J. Little (Eds.). Handbook of Experimental Pollination Biology. Van Nostrand Reinhold, New York, NY.
• Bartomeus, I., Ascher, J.S., Gibbs, J., Danforth, B.N., Wagner, D.L., Hedtke, S.M., & Winfree, R. (2013). Historical changes in Northeastern US bee pollinators related to shared ecological traits. Proceedings of the National Academy of Sciences of the United States of America, 110: 4656–4660.
• Buchmann, S.L. (1983). Buzz Pollination in Angiosperms. In Jones, C.E. and R.J. Little (Eds.). Handbook of Experimental Pollination Biology. Van Nostrand-Rheinhold Inc, New York, NY. 73–113.
• BugGuide. (2022). Genus Bombus - Bumble Bees. https://bugguide.net/node/view/3077.
• Bumblebee Conservation Trust. (2022). Flower Finder. https://beekind.bumblebeeconservation.org.
• Cameron, S.A., Lozier, J.D, Strange, J.P., Koch, J.B., Cordes, N., Solter, L.F., & Griswold, T.L. (2011). Patterns of widespread decline in North American bumble bees. Proceedings of the National Academy of Sciences of the United States of America, 108(2):662–7.
• Chayka, K. & Dziuk, P. (2022). Minnesota Wildflowers. https://www.minnesotawildflowers.info.
• Cole, J.S., et al. (2020). Plant Selection by Bumble Bees (Hymenoptera: Apidae) in Montane Riparian Habitat of California. Environmental Entomology, 49(1): 220–9.
• Colla, S. & Packer, L. (2008). Evidence for decline in eastern North American bumblebees (Hymenoptera: Apidae), with special focus on Bombus affinis Cresson. Biodiversity and Conservation, 17(6), 1379–1391.
• Colla, S., Richardson, L., & Williams, P. (2011). Bumble Bees of the Eastern United States. USDA Forest Service.
• Colla, S., Gadallah, F., Richardson, L., Wagner, D., & Gall, L. (2012). Assessing declines of North American bumble bees (Bombus spp.) using museum specimens. Biodiversity Conservation, 21:3585-3595.
• Cornell Entomology Outreach and Extension. (2014). Pollen Grains Reference Library. https://blogs.cornell.edu/pollengrains.
• Crompton, C.W. & Wojtas, W.A. (1993). Pollen Grains of Canadian Honey Plants. Research Branch Agriculture Canada. 1892/E.
• Crone, E.E. & Williams, N.M. (2016). Bumble bee colony dynamics: Quantifying the importance of land use and floral resources for colony growth and queen production. Ecology Letters, 19:460–468.
• Diblik, R. (2014). The Know Maintenance Perennial Garden. Timber Press.
• Erdtman, G. (1969). Handbook of Palynology: Morphology, Taxonomy, Ecology. An Introduction to the Study of Pollen Grains and Spores. Munksgaard.
• Federal Register (2017). Endangered and threatened wildlife and plants; endangered species status for Rusty Patched Bumble Bee. Federal Register 82:3186-3188.
• Fernald, M.L. (1950). Gray’s Manual of Botany, 8th ed. American Book Company.
• Flora of North America Editorial Committee. (1993). Flora of North America North of Mexico. New York and Oxford. http://beta.floranorthamerica.org.
• Fowler, J. (2020). Pollen Specialist Bees of the Central United States. https://jarrodfowler.com/bees_pollen.html.
• Fowler, J. & Droege, S. (2020). Pollen Specialist Bees of the Eastern United States. https://jarrodfowler.com/specialist_bees.html.
• Franklin, H.J. (1913). The Bombidae of the New World. Part I. Transactions of the American Entomological Society, 38:177– 486.
• Fuselier, E. (2021). Native Plants, Phytoremediation & Green Infrastructure: How Native Plants Can Be Used to Improve Environmental Quality. Wild Ones. https://wildones.org/phytoremediation-with-eric-fuselier/
• Glassberg, J. (1999). Butterflies Through Binoculars: The East. Oxford University.
• Gleason, H.A. & Cronquist, A. (1991). Manual of Vascular Plants of Northeastern United States and Adjacent Canada. New York Botanical Garden.
• Goulson, D. (2003). Bumblebees: Their Behaviour and Ecology. Oxford University Press.
• Goulson. D., Lye, G.C., & Darvill, B. (2008). Decline and conservation of bumble bees. Annual Revue of Entomology, 53: 191–208.
• Goulson, D., Nicholls, E., Botias, C., & Rotheray, E. L. (2015). Bee declines driven by combined stress from parasites, pesticides, and lack of flowers. Science, 347(6229).
• Halbritter H. (2005). PalDat – A Palynological Database. https://www.paldat.org/.
• Haines, A. (2011). Flora Novae Angliae. Yale University.
• Halbritter, H., Ulrich, S., Grímsson, F., Weber, M., Zetter, R., Hesse, M., Buchner, R., Svojtka, M., & Frosch-Radivo, A. (2018). Illustrated Pollen Terminology. Springer.
• Harmon-Threatt, A. (2011). Resource use of native bees: Understanding the roles of preference, nutrition, and competition. Ph.D. Dissertation. University of California.
• Harmon-Threatt, A. & Kremen, C. (2015). Bumble bees selectively use native and exotic species to maintain nutritional intake across highly variable and invaded local floral resource pools: Bee nutrition in invaded landscapes. Ecological Entomology, 40. 10.1111/een.12211.
• Heinrich, B. (1979). Bumblebee Economics. Harvard University.
• Hilty, J.A. (2022). Illinois Wildflowers. http://www.illinoiswildflowers.info/.
• Holm, H. (2014). Pollinators of Native Plants. Pollination Press.
• iNaturalist. (2022). Bumble Bees. https://www.inaturalist.org/taxa/52775-Bombus.
• I.U.C.N. (2022). The IUCN Red List of Threatened Species. Version 2021-3. https://www.iucnredlist.org.
• Jacobson, M. M., Tucker, E. M., Mathiasson, M. E., & Rehan, S.M. (2018). Decline of bumble bees in northeastern North America, with special focus on Bombus terricola. Biological Conservation, 217, 437–445.
• Jha, S., Stefanovich, L., & Kremen, C. (2013). Bumble bee pollen use and preference across spatial scales in human-altered landscapes. Ecological Entomology, 38(6):570–579.
• Kartesz, J.T. & The Biota of North America Program. (2015). North American Plant Atlas. http://bonap.net/napa.
• Kearns, C.A. & Thompson, J.D. (2001). The Natural History of Bumblebees. University Press of Colorado.
• LaBerge, W.E. & Webb, M.C. (1962). The Bumblebees of Nebraska (Hymenoptera, Apidae, Bombinae). University of Nebraska College of Agriculture.
• Lady Bird Johnson Wildflower Center. (2022). Native Plants of North America. https://www.wildflower.org/plants-main.
• Laverty T.M. & Harder L.D. (1988). The Bumble Bees of Eastern Canada. The Canadian Entomologist, 120: 965-987.
• Lhomme, P., Williams, S.D., Ghisbain, G., Martinet, B., Gérard, M., & Hines, H.M. (2021). Diversification pattern of the widespread Holarctic cuckoo bumble bee, Bombus flavidus (Hymenoptera: Apidae): The East Side Story. Insect Systematics and Diversity, 5(2):1-15.
• Lidtner, P. (2014). Garden Plants for Honey Bees. Wicwas Press.
• Lovell, H.B. (1926). The Honey Plants of North America. A.I. Root.
• Michener, C.D. (2000). The Bees of the World. Johns Hopkins University Press, Baltimore.
• Milliron H.E. (1973). A Monograph of the Western Hemisphere Bumblebees (Hymenoptera: Apidae; Bombinae). The Entomological Society of Canada, No. 89.
• Missouri Botanical Garden. (2022). Plant Finder. https://www.missouribotanicalgarden.org/plantfinder/plantfindersearch.aspx.
• Mitchell, T.B. (1962). Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 152.
• Moerman, D.E. (1998). Native American Ethnobotany. Timber Press. http://naeb.brit.org.
• Mola, J., Hemberger, J., Kochanski, J., Richardson, L., & Pearse, I. (2021). The Importance of Forests in Bumble Bee Biology and Conservation. BioScience. 71. 1234-1248. 10.1093/biosci/biab121.
• Mola, J., Richardson, L., Spyreas, G., Zaya, D., & Pearse, I. (2021). Long‐term surveys support declines in early‐season forest plants used by bumble bees. Journal of Applied Ecology. 58. 10.1111/1365-2664.13886.
• Native Land Digital. (2022). Native Land Digital. https://native-land.ca.
• Native Plant Trust. (2022). Go Botany (3.6). http://gobotany.nativeplanttrust.org.
• Newcomb, L. (1989). Newcomb’s Wildflower Guide. Little, Brown.
• Novotny, J.L, Lybbert, A., Reeher, P., Mitchell, R.J., & Goodell, K. (2023). Bumble bee banquet: Genus- and species-level floral selection by Midwestern Bombus. Ecosphere, 14(21).
• Ogren, T.L. (2015). The Allergy-Fighting Garden. Ten Speed Press.
• Omernik, J.M. (1987). Ecoregions of the Conterminous United States. Map (Scale 1:7,500,000). Annals of the Association of American Geographers, 77(1):118-125.
• Oudolf, P. & Kingsbury, N. (2013). Planting: A New Perspective. Timber Press.
• Pellett, F.C. (1976). American Honey Plants. Dadant & Sons.
• Peters, C.M. (2018). Sustainable harvest of wild plant populations. HerbalGram, 118: 44-49.
• Peterson, R.T. & McKenny, M. (1998). Peterson Field Guide to Wildflowers: Northeastern and North-central North America. Mariner.
• Plath, O.E. (1934). Bumblebees and Their Ways. Macmillan.
• Portman, Z.M., Orr, M.C., & Griswold, T. (2019). A review and updated classification of pollen gathering behavior in bees (Hymenoptera, Apoidea). Journal of Hymenoptera Research, 71: 171-208.
• Prairie Moon Nursery. (2020). Cultural Guide. Prairie Moon.
• Robertson, C. (1928). Flowers and Insects: Lists of Visitors of Four Hundred and Fifty-Three Flowers. The Science Press Printing Company.
• Roulston, T.H. & Cane, J.H. (2000). Pollen nutritional content and digestibility for animals. Plant Systematics and Evolution, 222(1):187.
• Roulston, T.H., Cane, J.H., & Buchmann, S.L. (2000). What governs protein content of pollen: Pollinator preferences, pollen-pistil interactions, or phylogeny? Ecological Monographs, 70(4):617–644.
• Schweitzer, D.F., Capuano, N.A., Young, B.E., & Colla, S.R. (2012). Conservation and Management of North American Bumble Bees. NatureServe, Arlington, Virginia, and USDA Forest Service, Washington DC.
• Seitz, N. & VanEngelsdorp, D. & Leonhardt, S. (2020). Are native and non‐native pollinator friendly plants equally valuable for native wild bee communities?. Ecology and Evolution, 10. 10.1002/ece3.6826.
• Strange J. & Tripodi, A. (2021). Characterizing bumble bee (Bombus) communities in the United States and assessing a conservation monitoring method. v1.5. USDA-ARS Pollinating Insect-Biology, Management, Systematics Research. Dataset/Occurrence. https://doi.org/10.1002/ece3.4783.
• Stuckey, I.H. & Gould, L.L. (2000). Coastal Plants from Cape Cod to Cape Canaveral. University of North Carolina Press.
• Sullivan, S.K. (2021). Wildflower Search. https://wildflowersearch.org/.
• Tallamy, D. (2020). Nature's Best Hope. Timber Press.
• Tallamy, D. & Alfandari, M. (2021). Homegrown National Park. https://homegrownnationalpark.org/.
• Tallamy, D., Fowler, J., & Garden for Wildlife (2021). Keystone Plants. National Wildlife Federation. https://www.nwf.org/Garden-for-Wildlife/About/Native-Plants/keystone-plants-by-ecoregion.
• Treanore, E., & Amsalem, E. (2020). The effect of intrinsic physiological traits on diapause survival and their underlying mechanisms in an annual bee species Bombus impatiens. Conservation Physiology, 8(1), coaa103.
• United States Department of Agriculture-Agricultural Research Service. (2012). Plant Hardiness Zone Map. https://planthardiness.ars.usda.gov/.
• United States Department of Agriculture-Natural Resources Conservation Service. (2022). The PLANTS Database. National Plant Data Team, Greensboro, NC. http://plants.usda.gov.
• The United States Fish and Wildlife Service. (2022). ECOS: Rusty Patched Bumble Bee. https://ecos.fws.gov/ecp/species/9383
• Vaudo, A.D., Tooker, J.F., Patch, H.M., Biddinger, D.J., Coccia, M., Crone, M.K., Fiely, M., Francis, J.S., Hines, H.M., & Hodges, M. (2020). Pollen protein: Lipid macronutrient ratios may guide broad patterns of bee species floral preferences. Insects, 11: 132.
• Williams, N.M., Cariveau, D., Winfree, R., & Kremen, C. (2011). Bees in disturbed habitats use, but do not prefer, introduced plants. Basic and Applied Ecology, 12(4):332–341.
• Williams, N.M., Mola, J.M., Stuligross, C., Harrison, T., Page, M.L., Brennan, R.M., Rosenberger, N.M., & Rundlöf, M. (2019). Fantastic bees and where to find them: Locating the cryptic overwintering queens of a western bumble bee. Ecosphere, 10: e02949.
• Williams, P. (2013). Bumble Bees of the World. Natural History Museum. https://www.nhm.ac.uk/research-curation/research/projects/bombus/.
• Williams, P. & Osborne, J.L. (2009). Bumblebee vulnerability and conservation world-wide. Apidologie, 40: 367-387.
• Williams, P., Thorp, R.W., Richardson, L., & Colla, S. (2014). Bumble Bees of North America: An Identification Guide. Princeton, N.J: Princeton University Press.
• Wood, T.J., Gibbs, J., Graham, K.K., Isaacs, R. (2019). Narrow pollen diets are associated with declining midwestern bumble bee species. Ecology, 100: e02697.
• Woodard, S.H., Duennes, M.A., Watrous, K.M., & Jha, S. (2019). Diet and nutritional status during early adult life have immediate and persistent effects on queen bumble bees. Conservation Physiology, 7(1):coz048.
• Xerces Society, The. (2012). Conserving Bumble Bees. The Xerces Society.
• Xerces Society, The. (2015). Cover Cropping for Pollinators and Beneficial Insects. Sustainable Agriculture Research and Education.
• Xerces Society, The. (2016). 100 Plants to Feed the Bees. Storey Books.
• Xerces Society, The. (2016). Collecting and Using Your Own Wildflower Seed. The Xerces Society.
• Xerces Society, The. (2016). Maintaining Diverse Stands of Wildflowers Planted for Pollinators. The Xerces Society.
• Xerces Society, The. (2016). Organic Site Preparation for Wildflower Establishment. The Xerces Society.
• Xerces Society, The. (2017). Pollinator Plants: Mid-Atlantic Region. The Xerces Society.
• Xerces Society, The. (2017). Pollinator Plants: Northeast Region. The Xerces Society.
• Xerces Society, The. (2018). Interseeding Wildflowers to Diversify Grasslands for Pollinators. The Xerces Society.
• Xerces Society, The. (2022). Habitat Assessment Guides. The Xerces Society.
• Xerces Society, The, Wildlife Preservation Canada, York University, University of Ottawa, The Montreal Insectarium, The London Natural History Museum, & BeeSpotter. (2022). Bumble Bee Watch. http://www.bumblebeewatch.org.

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