An easy to grow perennial that is tolerant of poor soils and difficult conditions. These reliable spreading plants will pack a punch of colour at the edge of the border or in the rock garden. In partiular, the variety I. s. 'Snowflake' (shown above) provides some of the purest white blooms in spring.
Suitable for rock gardens, scree or gravel beds, borders and path edging. Can be invasive.
For best results plant in small groups, 6 to 8in (15-20cm) apart, in a light, well draining, slightly alkaline soil, in full sun.
Water thoroughly during dry weather until well established. Mulch with organic matter in spring and add a general fertilizer such as bonemeal.
Trim lightly after flowering to maintain compactness.
Prone to slugs, snails, flea beatle and caterpillars.
Generally disease free.
Propagate from seed or semi-hardwood cuttings in mid-summer. Pot-up overwinter and plant out in the spring.