Bean family (Fabaceae)
Description: This perennial wildflower is 2-4' tall. It branches frequently into multiple major stems at the base, which divide into much smaller side stems. These stems are held stiff and straight at about a 45° angle from the ground or from each other. The entire plant has a shrub-like appearance that is vase-shaped at the base. It is herbaceous, notwithstanding appearances to the contrary, as all the stems die down to the ground each winter. Each stem is light green, round but strongly ridged, and covered with lines of appressed or slightly spreading white hairs. The lower stems become brown and woody with maturity, and they lose most of their hairs. The alternate compound leaves are trifoliate with short petioles. The leaflets are up to ¾" long and ¼" across. They are oblong or oblanceolate, and have smooth margins. The upper surface of each leaflet is dull green and hairless, while the lower surface is covered with silky appressed hairs. The blade of each leaflet often angles upward along the central vein, and it often has a fine point at its tip.
From 1-4 flowers develop from the axils of the compound leaves on short stalks. Each flower is about 1/3" (8 mm.) long, and has a typical pea-like structure consisting of a broad standard and narrow keel. The petals are white or cream, usually with a patch of purple at the base of the standard. The pubescent calyx has 5 long teeth that often turn purplish green. The blooming period usually occurs during early fall and lasts about a month. There is no noticeable floral scent. Each flower can produce a short pubescent seedpod containing a single seed. The root system consists of a stout taproot. This wildflower spreads by reseeding itself and can form large colonies.
Cultivation: This plant is usually found in full sunlight at sites that are mesic to dry. It grows quite well in a slightly heavy clay-loam soil, and it is not bothered much by foliar disease. Mature plants are quite drought tolerant.
Range & Habitat: The non-native Silky Bush Clover occurs occasionally in the southern half of Illinois, but it is rare or absent elsewhere within the state (see Distribution Map). However, this plant may be spreading steadily northward. It was introduced into the United States from east Asia. Habitats include fields, where it is occasionally planted as a source of forage and hay, and roadside banks, where it has been planted for erosion control. Other habitats include openings in upland woodlands, thickets, and prairie restorations. This species can invade many natural habitats and form dense colonies of plants. It is sometimes introduced into prairie restorations accidentally, probably as a contaminant of seed, and should be removed. The invasive potential of this species is quite high.
Faunal Associations: The flowers attract bumblebees and other long-tongued bees. The dagger bee, Calliopsis andreniformis, is a common visitor of the flowers of Lespedeza spp. The caterpillars of the skippers Thorybes pylades (Northern Cloudywing) and Thorybes bathyllus (Southern Cloudywing) feed on foliage of Lespedeza spp., as do the caterpillars of the moths Automeris io (Io Moth) and Utetheisa bella (Bella Moth). The seeds are eaten by some upland gamebirds, including the Bobwhite Quail and Wild Turkey, while the palatable foliage is eaten by White-tailed Deer and livestock.
Photographic Location: An upland area of a restored prairie at Meadowbrook Park in Urbana, Illinois, where this species was accidentally introduced.
Comments: Silky Bush Clover has a distinctive shrubby appearance with a V-shaped base. From a distance, the narrow leaflets resemble needles on the stems of an evergreen species. Its flowers are very similar in appearance to those of Lespedeza capitata (Round-Headed Bush Clover), but the latter species branches much less and its leaflets are longer and broader in size. Another common name for Lespedeza cuneata is Chinese Bush Clover.