Thunberg's lespedeza is a perennial flowering subshrub that is also commonly know as bush clover. Lespedeza throws blooms in shades of pink and lavender in the late summer and fall. Its foliage is a slightly dusty deep green blue and the small leaves grow in profusion on long arching stems. Thunberg's lespedeza is hardy in USDA zones 4a to 9b and thrives in sunny to partially shady sites. Maintenance pruning can be done throughout the growing season while significant structural pruning should always be done in the early spring before new growth appears.
Maintenance prune once a month or so just to remove any dead, diseased or damaged stems or foliage. You can cut back the entire stem down to its base or just as far as the damage appears, whatever gives a more pleasing and neat appearance. Inspect the plant each time you water so that you can stay on top of the plant's health and condition and spot problems quickly after they emerge.
Prune your lespedeza thunbergii annually to control spread, height and size in the late winter or early spring before new foliage growth begins to appear. Select stems that are crossing, drooping or otherwise crowding the shrub and cut them off at the base of the stem. Pull each stem from the shrub canopy as you make your cuts so that you can see your impact on the shape and symmetry of the shrub. Space your cuts throughout the shrub to maintain a balanced fountain-like appearance.
Hard prune or shear down your lespedeza to its trunk base in the late fall after the first frost. This is done in colder climates where it does not overwinter well. Since lespedeza blooms on new growth the next summer's bloom will not be disturbed. In warmer climes where lespedeza does not die back hard prune only if for some reason you want to start the plant anew in a temporarily smaller form.