Iris (bearded) iris
Height 7.5cm-1.5m (3in-5ft)
Planting distance 15-38cm (6-15in)
Flowersto mid summer
Any good garden
Open sunny position
Rhizomes available early to late summer
Bearded irises are a large group of irises that spread underground by means of rhizomes. Above ground, they are characterized by thick leaves arranged in a flat fan shape, andwith tufts of hair (beards) on the three outer petals (falls). The flowers, some of which are scented, come in a mass of colours. They are carried on strong stems above the spears of foliage between mid spring and mid summer.
All species and hybrids are fully hardy, so you can leave them in the ground over winter. They grow in most garden soils, but must be given an open sunny position. The most widely grown bearded irises belong to the Eupogon group, recognized by their grey-green leaves which die down to small fans in winter.
Popular species and hybrids
Bearded irises are divided into three groups, according to height. Dwarf bearded irises have flowers in mid and late spring on 7.5-25cm (3-10in) high stems. Plant the rhizomes in small clumps 15-20cm (6-8in) apart in well-drained soil in a rockery or at the edge of a raised border. Replant every two to three years. Iris pumila has flowers in shades of purple, white, yellow, and yellow with brown tints in mid spring. It stands only 10cm (4in) high and has no stem. As it grows naturally on mountains, well-drained soil in a rockery provides an ideal site. It’s advisable to divide the rhizomes every two years after flowering. Hybrids come in similar colours to I. pumila but tend to be taller — some reaching 25cm (10in) high. Popular varieties include ‘Bee Wings’ (yellow with brown spots on the falls), ‘Blue Denim’ (lilac-blue) and ‘Bright White’ (white). Intermediate bearded irises flower in late spring. They reach 25-70cm (10-28in) high. Plant 30cm (12in) apart at the front of a herbaceous border or in a large pocket in a rockery. Divide and replant every third year. Iris germanica, often called London flag or purple flag, has rich blue-purple falls with a white beard and light purple standards (upright inner petals). The sweetly scented flowers appear in early summer, 60-90cm (2-3ft) above ground. The foliage is evergreen.
Hybrids have well-shaped flaring flowers throughout late spring. They are vigorous, free-flowering and come in a range of yellows, creams, whites, purples and blues. Popular hybrids include ‘Arctic Fancy’ (purple and white), ‘Golden Fair’ (deep yellow), ‘Green Spot’ (pale cream with green ‘thumb’ marks on the falls) and ‘Langport Star’ (white).
Tall bearded irises flower in early summer on 75-150cm (2-½-5ft) high stems. The tallest varieties sometimes need staking. Plant the rhizomes 38cm (15in) apart. An enormous variety of hybrids is available in a range of colours. The most popular include ‘Amethyst Flame’ (amethyst), ‘Berkeley Gold’ (rich yellow), ‘Black Taffeta’ (black), ‘Desert Song’ (pale yellow), ‘Jane Phillips’ (pale blue), ‘Kent Pride’ (chestnut-brown), ‘Party Dress’ (flamingo-pink), ‘St Crispin’ (golden yellow) and ‘Staten Island’ (gold and red brown).
Plant the rhizomes from early to late summer in beds prepared with well-rotted manure, compost, bone-meal and a little lime. Arrange the rhizomes so they all face the same way – leaf-shoot end away from the sun. Plant so that the top of the rhizome is just visible above ground. Make sure the soil around them doesn’t dry out for the first two or three weeks after planting. Keep the weeds down and peel off any dead leaves. In winter cut back foliage to discourage slugs. In early spring apply a dressing of general fertilizer. Dead-head during the flowering season.
Every three years after flowering, divide the rhizomes by cutting off pieces from the outer part of the clump and discarding the centre. Make sure each piece has one or two strong foliage fans; replant immediately.