Bristly Locust (Rose Locust)

Size, growth and what to expect

Bristly locust is a colony more than a shrub. In a yard expect stems of 3 to 8 feet, though wild plants can reach 10, and a clump spreads 5 to 15 feet wide by root suckers. It grows fast, nearly three feet of new height a year on an average site in our growth estimator's model. It usually begins to flower in its second year.

Rose-pink pea flowers hang in clusters 2 to 4 inches long in May, and the name rose locust comes from that bloom. Bristly purple pods 2 to 3 inches long follow, each holding three to five seeds, and the stiff hairs on the branches, stalks and pods are what bristly means. Native bees and honey bees work the flowers, and highway crews have planted it to hold dry sand and to serve as a snow fence in the north.

It grows wild in the mountains from Virginia to Kentucky and south to Georgia and Alabama, in open woods, on mountain slopes and on sand hills, and it has spread far beyond that range.

How to grow Bristly Locust

Bristly locust needs full sun and dry to average soil; sand, road cuts and mine spoil suit it. The roots run, so plan on a colony several times wider than the stems are tall, and keep it away from lawn edges and beds. Set plants 5 to 15 feet apart.

Plant in the dormant season. Saplings ship bare-root or in pots, and because they start as rooted suckers the roots are shallow and wide. Dig wide rather than deep, set the crown at grade, refill with the soil you removed, and water it in. Mulch lightly, off the stems, and skip the stake.

Water through the first summer only. This shrub fixes its own nitrogen, so do not feed it; rich ground only makes it run harder. Rabbits and deer browse new shoots, so cage a young plant for its first two winters, then cut winter-killed tips back in spring.

Stems and pods carry stiff reddish bristles that catch on skin and clothing, so wear sleeves around it. The wood is brittle and breaks in ice and wind. It seldom sets seed, spreading instead by root suckers, which holds a bank and overruns a border. Wisconsin restricts its sale and transport, so we do not send it there.