Iberis umbellata is an annual plant originating in Spain. It is a distant relative of the cabbage.
Season & Zone
Exposure: Full sun – some afternoon shade is appreciated
Start indoors 6-8 weeks before last frost date, around early to mid-February on the coast. Or direct sow outdoors from your last date, every two weeks into July for a continuous bloom period. Seeds should germinate in 10-20 days. Ideal soil temperature for germination: 21-30°C (70-85°F).
If starting indoors, use peat or coir pots and bottom heat. Only cover seed by a couple of millimeters (1/8″) of soil. Transplant out after last frost at 15-30cm (6-12″) apart.
Iberis does not respond well to transplanting or being moved. Direct sowing may be simplest. Choose any well-drained garden soil with a neutral pH range of 6.0-7.0. Trim plants lightly after flowering to encourage a second bloom. Iberis may self sow.