Photo: Karen Guin, CC BY 4.0 · Wikimedia Commons

Tough Bully

Sideroxylon tenax

Also called tough buckthorn, tough bumelia, Bumelia tenax.

A thorny small tree of dunes and scrub with leaves silky gold to copper beneath, fragrant flowers that swarm with pollinators, and fruit for birds.

Drought tolerantSalt tolerantWildlife valueShowy flowersRare

Type: Small tree
Mature height: 12–30 ft
USDA zones: 8–10
Growth rate: Medium
Sun: Full, Part
Soil moisture: Dry, Average
Grows wild in: Sandy barrens, the coast and dry uplands
Native range: Florida, Georgia, North Carolina and South Carolina See what is native in your state

Hardiness zones Find your zone by ZIP code

Tough bully is a thorny small tree of the sapodilla family and a cousin of our gum bumelia. Its name, from the Latin for tough, fits a tree that thrives on dunes and in scrub, in drought, salty wind and poor sand. The undersides of its leaves are covered in silky hairs of gold to coppery brown, and its twigs bleed a milky sap when broken. North Carolina, at the north end of its range, lists it as threatened. Grow it where its silky leaf undersides can be seen, as a specimen or a thorny hedge on dry, sandy ground.

Size, growth and what to expect

Sources disagree on its pace: some call it fast in a garden, others slow, and wild plants in scrub grow slowly. Our growth estimator treats it as a medium grower, about a foot and a half a year. It makes a small tree of 12 to 30 feet with a crown 10 to 20 feet wide, or a bushy, thorny shrub on poor sand. It keeps its leaves in the south of its range and drops them farther north.

Clusters of up to 40 tiny, fragrant white flowers open in May and June, and bees, wasps, flies and butterflies swarm to them. A native bee of the Florida scrub, described in 2011, seems to visit no other flower. The fruit ripens purplish black in late summer and fall, a third to half an inch long and sweet. Birds and mammals eat it.

It grows wild on the coastal plain from southern North Carolina to Florida, on coastal dunes, in maritime forest and pinelands, and in inland scrub on deep sand. NatureServe ranks it vulnerable.

How to grow Tough Bully

Tough bully grows in full sun or part shade, in deep sand that drains fast. It takes long droughts and poor soil, and it stands salty wind, though not direct salt spray or flooding by salt water. Plant it 15 feet from a wall and at least 15 feet from overhead wires, and set trees 10 feet apart for a hedge.

Saplings ship bare-root or potted. Plant them from late fall to early spring, 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. It can be grown from seed cleaned of its pulp. Chill the seed damp in the refrigerator for 60 days, as gum bumelia seed is treated. Sow it in spring under a light cover of soil.

Water weekly through the first summer, then only in long droughts. Prune it young to one trunk for a small tree, or let it branch into a bushy shrub. Wear gloves, since the branches carry thorns.

Each flower carries both male and female parts, and most buckthorns can pollinate themselves, so a single tree can set fruit. The larvae of the bumelia borer, a longhorn beetle, can tunnel into the base of buckthorn trunks. It has no other significant pests or diseases.

Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them.

Sources (10)