Iberis umbellata is an easy-to-grow annual plant that is native to the Mediterranean region. It is a distant relative of the cabbage. The Latin name refers to the umbel flower form of the relatively flat grouping of many small individual flowers. As an umbel-forming plant, it is naturally attractive to a host of beneficial predatory insects. Continue reading below for tips on how to grow Iberis from seed.
Season & Zone
Exposure: Full sun – some afternoon shade is appreciated where summers are hot
Start indoors 6-8 weeks before last frost date. Or direct sow outdoors after the last frost 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 millimetres (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 is probably 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.