Corkwood

Size, growth and what to expect

Its growth rate is not recorded, so our growth estimator uses the medium rate, about a foot and a half a year. Its stems usually reach 5 to 10 feet and can reach 20. A plant spreads 4 to 12 feet as it suckers into a thicket. Its wood, at a specific gravity of 0.21, is lighter than cork and once floated fishing nets.

Catkins open in February and March, before the leaves, yellowish brown on male plants and dark red on female ones. Wind carries the pollen. Females then bear leathery, one-seeded fruit up to an inch long, ripe from late spring into July.

It grows wild along the Gulf coast of Florida and in two swamp systems of south Georgia, in freshwater and tidal marshes. In a freezing test, stems from Missouri survived far lower temperatures than stems from Texas, so hardiness depends on the seed source.

How to grow Corkwood

Corkwood grows best in full sun or light shade, in soil that stays wet, even under standing water for long spells. It tolerates average garden soil but thrives in wet ground. It takes brackish water as well as fresh. Plant it 6 feet from a wall, and set plants 6 feet apart for a thicket. At its size it can go within 15 feet of overhead wires.

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 crown at the soil line, put the native soil back in, and keep the mulch clear of the stems. Corkwood is hard to raise from seed. In a trial, ripe fruit sown soon after picking came up at 5 percent or less. Hold the fruit damp in the refrigerator for three months, then sow it a quarter inch deep in late September. Seedlings come up the next spring.

Water weekly through the first summer unless the ground stays wet on its own. Corkwood spreads by buds on its shallow roots, so cut or mow the suckers where you want the thicket to stop. Clear away taller woody plants that shade it, since it competes poorly in shade.

Most plants are male or female, and only females bear fruit, so plant three or more seedlings for a male and a female. No serious pest or disease troubles it. Caterpillars of the ailanthus webworm sometimes chew young leaves, but the damage needs no control.