Quick Guide: summer, hardy, full sun, height: 23cm/9in, width: 60cm/24in

There are three species of sub-shrubby perennial iberis, commonly called candytuft, suitable for the rock garden. All have dark green narrow leaves and bear numerous heads of densely packed flowers of white or lilac over a long period. As they are tolerant of polluted atmospheres iberis are a good choice for town gardens.

GROWING Plant between autumn and spring in any well drained garden soil. They thrive on poor soils.

PROPAGATION Take 5cm/2in softwood cuttings of non flowering shoots in summer. Place in a cold frame in a peat/sand mixture until rooted. Pot up individually and over winter in the frame, setting out the young plants the following spring.

SPECIES Iberis gibraltarica, semi-evergrcen, not full, hardy but self-seeds freely, lilac flowers in spring; I. saxatilis, only 7.5cm/3in high, spread 30cm/12in, neat form, white flowers spring to summer; 1. sempernirens, variable in form. The variety `Little Gem', with white flowers, is neat at 10cm/4in high, spread 23cm/9in; `Snowflake' has pure white flowers and is more spreading in habit.

POSSIBLE PROBLEMS Flea beetles may puncture the leaves.