💨 Smoke Bush

What it looks like

How to grow

Plant in spring in full sun and well-drained soil — smoke bush is grown for its summer ‘smoke’: airy plumes of tiny flower hairs that turn pink, purple, or smoky gray and hover over the foliage for weeks. ‘Royal Purple’ pairs purple leaves with pink smoke; ‘Golden Spirit’ offers chartreuse foliage. It tolerates poor, rocky soil and drought once established, but it will not tolerate wet feet. Give it space — a smoke bush crammed against a house loses the billowing shape that justifies it.

Water & feeding

Water to establish; mature plants are drought-tolerant and need little supplemental water. Overwatering in heavy soil causes more trouble than drought.

Common problems

• Verticillium wilt — rare, but avoid planting where susceptible plants have died of it
• Few insect pests of note
• Leggy growth in shade — full sun is essential for dense form and good smoke

Harvest

Prune in early spring: either lightly shape it, or coppice (cut to near ground level) every few years for larger leaves and a shrubbier habit — coppiced plants bloom less but grow spectacular foliage.

Saving seeds

Smoke bush seed is a patience test with a hard shell and a double dormancy — and it will not sprout without both treatments. The seed coat is water-impermeable, so start by pouring very hot (almost boiling) water over the seed and soaking it for 12 to 24 hours, or nick the coat with a file. Then give it a sustained cold period: 60 to 90 days in the fridge in damp mix is the common figure, though some sources call for two to three months warm first and then two to three months cold, and the ranges disagree. Without pre-treatment, 10% or less of the seed germinates in the first season.

After chilling, sow about 1 cm deep in pots at 15 to 20°C, and germination usually comes within four weeks in ideal conditions — though it can drag on for 12 months or more, and in the wild the seed may wait out several winters as insurance. Slightly immature “green” seed germinates more readily than fully ripe seed, so collect a little early if you can. Sow more than you need and do not give up on the tray.

Smoke bush is dioecious — separate male and female plants — and the smoky plumes are the female flowers, so seed only comes from a female with a male nearby. Named cultivars, especially the purple-leafed ones, come only from cuttings, and cuttings from a female tree are preferred precisely because they give you the smoke. Seedlings will vary in color and in how smoky they get.

And the Florida honesty: smoke bush is a cold-hardy shrub for zones 4 to 8 that wants a real winter and dry, rocky soil, so it is marginal in Florida — north Florida only, in the sunniest, best-drained spot you have, and even there it is a stretch. If it thrives, it is earning its keep against the climate.

Varieties

Every named variety of Smoke Bush with its own growing guide:

• Golden Spirit Smoke Bush — The gold smoke bush: chartreuse-gold leaves all season, pink smoke in summer, and the brightest shrub in the border.
• Grace Smoke Bush — The biggest, smokiest smoke bush: a hybrid with huge pink plumes and purple-green leaves, for gardens with room to let it go.
• Royal Purple Smoke Bush — The purple smoke bush that started it all: dark purple leaves, pink-purple smoke, and a shrub that looks lit from within.