Western Soapberry

Size, growth and what to expect

Western soapberry grows at a medium pace, about a foot and a half a year in our growth estimator. Expect a tree of 20 to 50 feet with a rounded crown 25 to 30 feet wide. It stays small in shallow soil and grows larger in deep soil.

Large clusters of creamy white flowers, up to 10 inches long, open in May and June. On female trees the berries, about half an inch across and see-through yellow, ripen in September and October. They turn black and hang on into late winter. Birds eat them, doves and songbirds nest in the crown, and the leaves feed the caterpillars of the soapberry hairstreak. The leaves turn yellow-gold in fall.

It grows wild from southwest Missouri and Kansas to Louisiana, Texas, New Mexico, Arizona, southern Colorado and northern Mexico. Look for it along streams, on dry limestone uplands and rocky hillsides, and at wood edges. NatureServe ranks it imperiled in Missouri and Colorado.

How to grow Western Soapberry

Western soapberry takes full sun or part shade, in dry to average soil that drains well. It grows in clay, sand or rocky limestone ground, takes alkaline soil and stands long droughts once established. It can sucker into a grove on a good site, so give it room. Plant it 15 feet from a wall and more than 50 feet from overhead wires, and set trees 25 feet apart.

Saplings ship bare-root or potted. Plant them dormant, from leaf fall until bud swell, in a hole wider than the roots and no deeper. Set the root flare at the soil line, put the native soil back in, and keep the mulch clear of the trunk. Soak the cleaned seed in cold water for five to seven days. Seed that swells can be sown three quarters of an inch deep, in fall or spring. Seed that stays small and hard needs hot water poured over it, then 60 to 90 days damp in the refrigerator before a spring sowing.

Water every week or two through the first summer, then only in a long drought. Seedlings put their first years into a strong taproot, so expect little top growth at first. Deer seldom browse it, but a tube keeps rabbits off the young stem. Pull or mow suckers where you want a single trunk.

Most trees are male or female, and only females bear the golden berries, so plant three or more seedlings for a male and a female. Female trees bear heavy crops nearly every year. Powdery mildew, leaf blight and leaf spot may appear in some areas. In Texas the soapberry borer, a beetle from Mexico first reported there in 2003, has spread to about 50 counties. Infested trees die back from the top and may die within three years, and soapberries show little resistance. The berries are poisonous if eaten, causing nausea, vomiting and diarrhea.