Height: 45-120cm (1”’j-4ft)
Water depth: 2.5-30cm (1-12in)
Features:spring to summer
Soil: deep, lime-free, moist
There are Four species, and many varieties, or iris for waterside use:ensata, I. variegata. Pseudacorus and I. versicolor. All have dramatic, upright, sword-shaped and attractive flowers in late spring to early summer.
Popular species and varieties:
Iris ensata (syn. I. kaempferi) (Japanese clematis iris) grows 60-75cm (2-2 1/2ft) tall, it prefers damp soil or very shallow water, 2.5-5cm ( 1-2in) deep. Its large flowers come in mauve, white, purple and blue.
‘Variegatus’ has green and cream striped foliage and purple flowers. Iris laevigata (Japanese water iris) grows best in a water depth of up to 15cm (6in). It has smooth, pale green leaves reaching 45-60cm. In early summer, three deep royal blue flowers open at the end of each. Varieties include ‘Atropurpurca’ (purple flowers), ‘ Queen’ (rose-pink), ‘Snowdrift’ (white and yellow) and ‘Variegata’ (blue (lowers, silverstriped leaves).
Iris pseudacorus (yellow flag or yellow water iris) grows in up to 30cm (1 ft) of water. Reaching 90-120cm (3-4ft), it has blue-green, ridged leaves. The branchingcarry five or more yellow flowers sometimes marked with brown veins, in late spring and early summer.
Varieties include ‘Golden Queen’ (golden flowers), ‘Sulphur Queen (primrose-yellow) and ‘Variegata’ (gold variegated spring leaves). Iris versicolor (American blue flag) grows to 45cm and produces distinctive, plum-coloured blooms with yellow markings. It thrives in 5-10cm (2-4in) of water. A popular variety is ‘Kermesina’, with wine-red flowers flecked with white.
Plant along the margins ofor streams in good, deep, moist, lime-free soil in early to mid spring. Divide and replant clumps every three years.
Propagation: Divide the rhizomes after flowering. Replant immediately.
Pests and diseases: Trouble free.