American senna is a herbaceous perennial in the Fabaceae (pea) family native to moist forested areas and disturbed sites in eastern North America. This is a striking plant while in bloom and has attractive foliage. The showy yellow flowers develop and grow into dark brown seedpods that attract birds and add winter interest to the garden. American senna do well in partial to full sun, and moist to mesic conditions. A rich loamy soil is preferred, although sandy and rocky soils are also tolerated. It doesn't mind an occasional flooding. This plant can become quite tall when the soil is fertile and moist. It may flop over while the flowers and seedpods are developing. This plant is drought tolerant once established. It is easy to propagate by seeds dropped by the plant or started in the early fall or by the division of roots in the early spring or fall. Plan to cut back mature seed heads in the late summer/early fall to control the number of plants in the garden. Full sun aids in better flowering. The American senna is a host plant for various Sulphur butterflies. Before the butterflies emerge, foliage and flower buds are often eaten by the caterpillars. The seeds may be eaten by some upland gamebirds as well, particularly the Bobwhite. The plant has many medicinal uses. The Cherokee and other peoples use the root of the plant to treat high fevers, a worm remedy, fainting spells and to pneumonia. The American senna is most often found on riverbanks, in moist meadows, pastures, and roadsides. Some disturbance of the plant location is beneficial to allow it to grow without it being overtaken by other trees and shrubs. Occasionally, American senna is found in flower gardens because of its showy flowers. Insects, Diseases, and Other Plant Problems: Foliage and flower buds are often eaten by the caterpillars of the Cloudless Sulphur Butterfly. Otherwise, they have no serious insect problems. Grown in rich soil it can flop over when flowering and may need support.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter; Loam (Silt); Sand; Shallow Rocky
Soil pH
Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist | Occasionally Wet
Available space
12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 4 ft. 0 in. - 6 ft. 0 in. | Width: 3 ft. 0 in. - 4 ft. 0 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
3 - Shrub (3-15 ft)
Form & Appearance
Habit / form
Rounded
Texture
Fine
Foliage
Deciduous
Leaf color
Gray/Silver; Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately)
Leaf arrangement
Alternate
Leaf shape
Elliptical; Oblong
Leaf margin
Entire
Leaf feel
Smooth
Leaf value
Showy
Leaf size
1-3 inches long, < 1 inch wide
Hairs present
No
Leaf detail
Compound pinnate leaves 5-10 pairs of gray green leaflets 2 1/2" long and 3/4" wide. Leaflets are oblong, elliptic with a pointed tip. At the petiole base are two lanceolate stipules that fall off.
Flower color
Gold/Yellow; White
Flower value
Showy
Flower form
Panicle; Raceme
Flower shape
Cup
Flower size
< 1 inch
Flower detail
Butter yellow, not typical pea-like flowers, raceme or panicle of flowers 1/2"-1" long. Flowers have 5 yellow sepals, 5 yellow petals, 10 dark brown stamens. Petals whiten as they age from mid- to late summer. There is no floral scent.
Bloom time
Summer
Fruit color
Brown/Copper
Fruit type
Legume
Fruit size
> 3 inches long, < 1 inch wide
Fruit detail
Flattened pods 4" long 1/2" wide, dark brown at maturity with 10-18 segments each containing a seed.
Stem color
Green
Stem detail
Light green stout central stem, slightly hairy in the upper stem
Wildlife & Ecology
Native status
Native
Origin
Eastern Northern America
Distribution
New England to Georgia, west to Illinois and Wisconsin
Wildlife value
Bumblebees are attracted to pollen. Birds enjoy the seeds particularly Bobwhites. Larval host plant of various types of Sulphur butterflies. Insects like ladybird beetles, ants and flies eat the nectar at the glands found at the base of the petioles because the flowers are nectar-less.
In the 9th century, Arab physicians used to brew the leaves to make a cathartic tea. The leaves and seeds are used today as a laxative. The Cherokee and other peoples use the root of the plant to treat high fevers, a worm remedy, treat fainting spells and to treat pneumonia.