by Don Gustafson
Why not include some pea-family legumes in your pollinator garden? They not only attract pollinators (bees, wasps, butterflies, moths, beetles and flies), but they also enhance biodiversity, improve the visual landscape and provide the additional benefit of increased fertility. As legumes, they all have specialized nodules on their roots that have the ability to “fix” nitrogen from the atmosphere. They are a great asset for soil enrichment.
The pea family (Fabaceae) is a large and varied group of plants most often associated with prairies, meadows and roadsides. It includes all species of clover, indigo and tick-foils that thrive in hot prairie sun. There are many to choose from, but the legumes that have proven successful in my pollinator garden are listed below.
Purple prairie clover (Dalea purpurea): Slender, erect plants that reach about two inches tall. Flowers are bright purple-magenta, with five protruding orange stamens. The flowers at the bottom of each spike bloom first, forming a brilliant wreath that climbs the spike as flowering progresses during late spring/summer. Like the white prairie clover, this plant was used by Native Americans to make brooms and brew tea. These plants should be protected when newly planted because they’re the favorite food of rabbits.
Round-headed bush clover (Lespedeza capitata): A slender, unbranched legume that grows to five inches high and is covered with fine, silvery hairs. The creamy-white flowers occur in dense, rounded heads that bloom between July and October. The creamy-white flower turns into showy brown seed heads in the fall. This is a favorite food of goldfinches and wild turkeys.
White wild indigo (Baptisia alba): Smooth, hairless, bushy plants that grow to six inches tall. The flowers are white, up to one inch long and bloom between May and August. The flower spikes are followed by black seed pods that rattle in the wind. Although it is slow growing, it is long-lived because of its deep roots.
Cream wild indigo (Baptisia bracteata): A course, hairy, bush-like plant with spreading branches up to two inches tall. The flower spike, up to one inch long, droops with numerous pale-yellow flowers. They bloom between May and August. The seed pods are black, pointed at the tip, and up to two inches long.
Leadplant (Amorpha canescens) derives its name from the gray color of the leaves, which contrast nicely with the purple flowers. A small shrub, up to three inches tall, with grayish hairs on a stem that becomes woody with age. The tiny purple flowers are in a spike-like mass along the upper part of the stem. The plant is often used as an indicator of a virgin prairie and is so deep-rooted that it is virtually drought-resistant.
Partridge pea (Chamaecrista fasciculata): No list of legumes would be complete without mentioning the charming partridge pea. This fragile annual that is tolerant of foot traffic and compacted soils shows up along the paths of my garden where nothing else seems to grow. Its yellow flowers bloom most of the summer, and its leaves fold up at night or when touched. This tactile sensitivity is a delight to school children and is a standard in a naturalist’s “bag of tricks.” It is a welcome visitor every year because it reseeds readily.
Other legumes worth planting are wild lupine (Lupinus perennis). The blue-violet
spikes of its flowers make a huge visual impact. Lupines don’t compete very well in rich soil and seem to need a sandy, less fertile and cool habitat. The endangered Karner blue butterfly is dependent on this plant as a larval food source.
White prairie clover (Dalea candida) is similar to purple prairie clover, but it has a larger flower. White prairie clover blooms from the stem up, which gives the two-foot flower a thimble-like appearance. White prairie clover is drought-resistant, with roots that penetrate up to five inches in the soil.
False blue indigo (Baptisia australis) is a handsome legume that will complement your early prairie bloom. This legume has showy, blue flower spikes followed by seed pods that rattle in the wind. Although somewhat vigorous, this bush-like flower is not invasive.
Finally, a word of caution: Although legumes are an integral part of any prairie plant community, restraint should be used in a home pollinator garden. In friable, fertile soil, many of these plants can be somewhat aggressive because of their nitrogen-fixing ability. Keep this in mind as you make your selections, and limit your use of tick-trefoils and especially vetches.
Sources: Illinois Wildflowers by Don Kurz, “The Pea Family Thrives in Hot Prairie Sun” by Cary George