Shrub lespedeza (Lespedeza bicolor) is a bushy, flowering legume. In many areas, shrub lespedeza was originally introduced to support wildlife and for use as an ornamental garden plant. Now, however, the shrub lespedeza is considered an invasive species.
I. Appearance and Characteristics
Lespedeza bicolor is a species of flowering plant in the legume family known by the common names shrubby bushclover, shrub lespedeza, and bicolor lespedeza. It is native to eastern Asia, ranging from southeastern Siberia to eastern China, Mongolia, Korea, and Japan. and it is widely grown as an ornamental plant. In some regions, such as the southeastern United States, it grows in the wild as an introduced and invasive species.
This plant is quite variable in appearance, and it has been bred into a number of cultivars. In general, this plant is an erect shrub growing to 3 meters (9.8 feet) in height and width, generally remaining smaller in cold climates. It can grow from ground level to 5 feet (1.5 meters) in one growing season. The cultivars “Little Buddy” and “Yakushima” grow to 3 feet (0.91 meters) and 1.5 feet (0.46 meters), resp. Lespedeza bicolor grows from a thick root system. The stems may be 3 centimeters (1.2 inches) in diameter. The leaves are each made up of three oval leaflets up to 5 centimeters (2.0 inches) long. The inflorescence is a raceme of up to 15 open pea like flowers, which are pink and purple in color. There are also cleistogamous flowers which self-pollinate and do not open. The fruit is a flat legume pod nearly a centimeter long which contains one seed.
This species was first introduced to the United States as an ornamental shrub in 1856, and it was likely introduced several times after that. In the 1930s it was recommended for use as erosion control and in the revegetation of abandoned mine sites. It was used to enhance wildlife habitat, particularly for the northern bobwhite. The United States Department of Agriculture produced and distributed the seed and many millions were planted. A number of strains and cultivars were developed to improve the plant’s drought tolerance and seed production.
It can grow in many types of habitat, including disturbed areas. By the 1990s the plant had escaped cultivation and taken hold in many regions of the eastern United States, especially those in the Southeast. In the US, it is now present from New York to northern Florida and as far west as Nebraska and Texas. It can be found as far north as Ontario in Canada.
In some areas this plant can form dense stands, becoming an aggressive invader. It has been considered threatening in areas where it has disturbed or prevented the growth of native plants, including grasses and trees. It may spread after fire, interfering in schedules of controlled burns of fire-adapted habitat types.
II. How to Grow and Care
Watering
Originating from East Asia, shrub lespedeza thrives in conditions that mimic its natural habitat with moderate humidity. It exhibits a preference for well-drained soil and has a notable drought tolerance once established. For optimal growth, shrub lespedeza requires watering once every two weeks, aligning with its ability to withstand periods of dryness. Typically grown outdoors due to its size and seasonal bloom, shrub lespedeza benefits greatly from the natural rainfall patterns, which complement its water cycle and reduce the need for supplemental irrigation during the growing season.
Fertilizing
For shrub lespedeza, use balanced nutrition fertilizers in spring to support vigorous growth and high nitrogen fertilizers before blooming to enhance flowering. Fertilize bi-annually, with no more than 1 pound per 100 square feet. Avoid over-fertilization to prevent growth at the expense of flowering. Adjust feeding with seasonal changes: less in fall, none in winter. Apply fertilizer evenly around the base and water thoroughly. This regimen will ensure healthy, resilient growth and optimal flowering in shrub lespedeza.
Propagation
Shrub lespedeza is best propagated during autumn and winter through preferred techniques such as cutting and layering. This plant poses moderate propagation difficulty. Success is indicated by new growth, and consistent moisture is crucial for optimal results.
Transplanting
The prime time for transplanting shrub lespedeza is during late summer to early fall (S3-S4 period) as this aids root establishment. A well-draining sunny location is ideal for successful transplantation. Remember, a bit of gentle firming ensures proper root-soil contact.
Repotting
Repot shrub lespedeza in early spring, every 2-3 years, to accommodate its growth as a sizable, bush-type plant. A larger pot with ample drainage promotes healthy development. After repotting, ensure shrub lespedeza receives consistent moisture without waterlogging. Minimal post-repotting care is required, but a light fertilizer can aid in recovery. Aim for friendly engagement with shrub lespedeza, encouraging its vibrant growth.
III. Uses and Benefits
Shrub lespedeza is an open-growing, loose shrub or subshrub that produces many pea-like pinkish flowers during its late summer flowering season. It is good to use for borders, in open woodland gardens or naturalized areas, planted in groups or masses; it is also effective in controlling erosion.
