Lespedeza thunbergii 'Spring Grove'

By late summer, when many shrubs have said their piece, Lespedeza thunbergii 'Spring Grove' is only clearing its throat. The many woody, arching stems bend into a green fountain through the season, then bow lower still under a long, generous fall of rose-purple pea flowers carried in racemes six to eight inches long. 'Spring Grove' is a newer selection said to hold darker purple flowers and a tidier, better habit than the old standard 'Gibraltar', and the photographs here come courtesy of the JC Raulston Arboretum.

Bush clover belongs to the legume family, Fabaceae, and like other legumes fixes nitrogen from the air, thriving in the lean, infertile soils that defeat hungrier plants. The genus name hides a small comedy of errors: the French botanist André Michaux meant to honor Vicente Manuel de Céspedes, the Spanish governor of Florida who aided his travels, but the name came out garbled as Lespedeza when the Flora Boreali-Americana went to print in 1803, and the misprint has stuck ever since. The epithet thunbergii honors Carl Peter Thunberg, the Swedish naturalist who collected the species in Japan in the 1770s.

This is a shrub that behaves like a perennial. The woody top dies back over winter, and because bloom comes on new growth, the tangle of dead stems can be cut clean to the ground in late winter or early spring with no loss of flower. What returns is fast and fountain-like, four or five feet of arching stem clothed in soft, trifoliate, clover-green leaves. Give 'Spring Grove' full sun and room to arch, and set the shrub where the cascade can spill over a wall, anchor the back of a border, or soften the edge of a bed.

Native across the eastern Himalayas, China, Korea, and Japan, bush clover has long been a plant of the East Asian late-summer garden, admired in Japan among the traditional flowers of autumn. The pea flowers hum with bees at a season when nectar runs short, and the plant asks almost nothing in return: no rich soil, little water once established, and no serious pests. Pair the rose-purple racemes with ornamental grasses, asters, and the gold of late rudbeckia for a border that peaks exactly when summer tips into fall.