Prairie Forbs

Illustrations by Linda S. Ellis

Forbs are broad leaved flowering plants. Many consider the native forbs found on our prairies to be weeds, when in reality many are valuable forage plants or legumes that build and enrich the soil. Many forbs are found often enough under the same conditions that they are considered "indicators" of these conditions. This pamphlet will assist in identifying some of the most common prairie forbs and what they indicate.

Plants are listed by how they respond to disturbance or usage by man. Decreasers are desirable plants that are most liked and sought after by livestock. Repeated improper usage causes them to decrease in abundance and vigor. Increasers are not as readily selected due to palatability or other reasons. Initially they increase in numbers following misuse of the prairie, then decline as abuse continues. Proper management will maintain the two groups in balance. There are many species similar to those shown--for further help in identification or prairie management contact your local SCS office or the Missouri Department of Conservation.

Decreasers

Leadplant (Amorpha canescens)

• Up to 1 1/2 feet. Blooms May to August. Legume.
• Indicator of moderate deep soils, also found on shallow sites. Leaves gray leadlike in appearance. Similar species, Indigo bush grows in wet areas.

Rattlesnake Master (Eryngium yuccifolium)

• Up to 5 feet. Blooms July to August.
• On most soils it disappears with overgrazing. Leaves resemble common yucca.
  

Pale Purple Coneflower (Echinacea pallida)

• Up to 3 feet. Blooms May to July
• May form large stands on moderate to deep soils. Chemicals in roots used by pharmaceutical companies.
  

Compass Plant (Silphium laciniatum)

• Up to 8 feet. Blooms July to September.
• Moderate to deep soils, will not tolerate heavy grazing. A gumlike substance from wounds on plant was chewed by Indians.
  

Gerardia (Gerardia tennifolia)

• Up to 4 feet. Blooms August to October
• Most common on moderate to shallow soils. Late flowering time makes it ideal indicator of disturbed prairie sites.
  

Illinois Bundleflower (Desmanthus illinoensis)

• Up to 5 feet. Blooms June to August. Legume.
• Adapted to most soils. Does well in plantings. Brown bundles of pods persist through winter.

Goats Rue (Tephrosia virginiana)

• Up to 1 1/2 feet. Blooms May to August. Legume.
• Indicator of shallow soils. Natural source of rotenone use by Indians to kill fish.

Virginia Lespedeza (Lespedeza virginica)

• Up to 3 feet. Blooms May to September. Legume.
• Shallow to moderate soils. Often confused with white flowered Sericea but more palatable. Excellent quail food.

Ashy Sunflower (Helianthus mollis)

• Up to 4 feet. Blooms July to October.
• Shallow to moderate soils. One of eight native sunflowers highly selected by livestock. They are sensitive to grazing.

Thickspike Gayfeather (Liatris pycnostachya)

• Up to 5 feet. Blooms July to September.
• Found on moderate to deep soils. This ornamental is used in native plantings. All members of this group sensitive to grazing.

Rough Blazing Star (Liatris aspera)

• Up to 4 feet. Blooms August to October.
• Found on shallow to moderate deep soils. Seldom forms dense strands like Thickspike Gayfeather.

Downy Gentian (Gentiana puberulenta)

• Up to 1 foot. Blooms September to November.
• One of last flowers to bloom in fall. They close during dim light conditions. Moderate to deep soils. Several stems form clumps.

Sensitive Briar (Schrankia uncinata)

• Foot tall-vining, 2-3 foot stems. Blooms May to August. Legume.
• Notable on stony shallow soils but thrives on deeper soils. Stems and pods covered with clawlike spines. Leaves close when touched. Very nutritious and high in protein.

Roundhead Lespedeza (Lespedeza capitata)

• Up to 4 feet. Blooms July to September. Legume.
• Flowers clustered on top, turn brown and persist through winter. With deep branching roots. Occurs on most soil types.

Purple and White Prairieclover (Petalostemon purpureum and P. candidum)

• Up to 2 feet. Legumes
• Flowering begins in May with the larger leaved white ending in July and the purple persisting through September. Found on shallow to moderate soils.

Increasers

Goldenrods(Solidago spp.)

• Up to 5 feet. Blooms July to November.
• Nine common types. Tall Goldenrod found on deeper soils causes most concern. Proper management will control them.

Asters (Aster spp.)

Up to 5 feet. Blooms July to October.

Twelve types are common. In general the white flowered ones are less desirable than the bluish ones. Rarely eaten by livestock when mature.

Rosin-Weed (Silphium integrifolium)

• Up to 6 feet. Blooms July to September.
• Often confused with desirable Ashy Sunflower. Found on all sites but most common on moderate soils.

Indian Paint Brush (Castilleja coccinea)

• Up to 1 foot. Blooms April to June.
• Found on all but deeper soils. Indicates continuous late haying but disappears with proper management.

Long-Bracted Wild Indigo (Baptisia leucophaea)

• Up to 1 foot. Blooms April to June. Legume.
• Indicates shallow to medium soils. Persists under extreme abuse as it is palatable only in dry hay.

White Wild Indigo (Baptisia leucantha)

• Up to 5 feet. Blooms May to July. Legume.
• Most common on deeper soils. Similar species Blue Indigo found on shallow to moderate soils.

Copyright 1986 by the Conservation Commission of the State of Missouri.

Document ID: --
Content revision: 20030707

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