The genus Lespedeza, commonly known as bush clover, includes approximately 45 species of flowering plants in the pea family (Fabaceae). These plants are widespread, hardy, and known for thriving in poor soils. While some species are native to eastern North America, most originate from eastern and southern Asia, where they are sometimes referred to as Japanese clovers. This guide details the physical characteristics used to identify Lespedeza.
General Classification and Growth Form
The appearance of Lespedeza depends on whether it is an annual or a perennial species. Annual lespedeza, such as common lespedeza (Kummerowia striata), exhibits a low, sprawling, and freely-branched growth habit, often forming dense mats across the ground. These annual types typically remain shorter, reaching heights of up to 18 inches.
Perennial lespedeza, most notably Sericea lespedeza (L. cuneata), grows as an upright, shrubby plant with clustered stems that can become somewhat woody near the base. This group reaches a greater height, commonly growing between 2 to 6 feet tall, presenting a much more bushy appearance. The difference in growth habit is a primary indicator of the type of lespedeza observed.
Key Identifying Features: Leaves, Flowers, and Stems
Leaves
The primary characteristic of the Lespedeza genus is its trifoliate leaf structure, meaning each leaf is composed of three leaflets, arranged alternately along the stems. These leaflets are often small, generally measuring between a quarter-inch to one inch long, and can range in color from green to an ashy-green. The shape is typically oblong to wedge-shaped.
Sericea lespedeza is known for its wedge-shaped (cuneate) bases that narrow abruptly toward the stem. The lower surfaces of perennial varieties are often covered with dense, silky white hairs, giving them a silvery appearance. Small, leaf-like appendages called stipules are present at the base of the leaf stalk.
Flowers
Lespedeza flowers are small, pea-like, and bilaterally symmetrical, typical of the Fabaceae family. Flower color includes rose-purple, pink, or white, with some perennial types displaying cream-white or yellowish flowers often marked with purple or pink throats.
The blooms appear in clusters. Annual species have solitary flowers or small spikes in the leaf axils, while perennial species have clusters of two to four flowers at the junction of the leaf and stem.
Stems
Annual varieties feature freely-branched, slender stems that may have hairs pointing downward. Perennial species like Sericea lespedeza have long, coarse stems that become distinctly woody and fibrous as they mature, especially near the base, and exhibit prominent branching.
Where and How Lespedeza Thrives
Lespedeza species are adapted to warm, humid climates and demonstrate a remarkable tolerance for adverse conditions. The plant is known for its ability to grow in poor, disturbed, or eroded soils because it forms a symbiotic relationship with nitrogen-fixing bacteria in its roots, which helps improve soil fertility.
It thrives in full sun but can tolerate partial shade. It is commonly found along roadsides, in old fields, pastures, prairies, and open woodlands. The life cycle is marked by prolific seed production. Many seeds are “hard” and require scarification to germinate, ensuring a persistent seed bank. The extensive root system, particularly the deep, woody taproot of perennial Sericea lespedeza, helps the plant withstand drought.