IRIS

The stately Irises which grow to a height of 3 ft or more in the centre of the herbaceous border belong to the Rhizome group – the Bulb group are smaller and belong in the rockery or the front of the border. Many useful varieties belong here – dwarfs which peep through the snow in January to large-flowered plants which bloom in July to the delight of the gardener and flower arranger. Survival over the winter can be a problem – a few types are rather tender and nearly all of them require sandy, well-drained soil to prevent rotting.

VARIETIES: There are 3 basic sections. The Reticulata group are dwarfs with flower stems 4-6 in. high and bloom in late winter or early spring. There are 2 old favourites – I. danfordiae (February-March, yellow scented flowers) and I. reticulata (February-March, purplish blue scented flowers with yellow markings). The flowers are about 3 in. across – for larger and earlier flowers grow I. histrioides ‘Major’ (January-February, blue flowers with white and gold markings). Plant the round bulbs 2 in. deep in September-October – set them 4 in. apart. The Juno group has distinctive bulbs – at the base there are thick roots which should not be broken when planting. The flowers are quite small (2-3 in.) but the flower stems are taller than the Reticulatas, reaching 1-1.5 ft. Set out the bulbs in September or October, planting them 2 in. deep and 6-9 in. apart. A neglected group – few gardeners will know I. bucharica (April, cream and yellow flowers) and I. aucheri (April, lilac and yellow flowers). The summer-flowering Xiphium group are popular, especially as cut flowers. The many named varieties in this large group should be planted 4-6 in. deep in September or October, leaving about 6 in. between them. The flower stalks grow 1-2 ft high. Earliest to flower are the Dutch Hybrids (June) – ‘Wedgwood’ (pale blue) is the favourite variety, but white, yellow, purple and blue types are available. The Spanish Hybrids bloom a few weeks later in early July – generally smaller in all their parts than the Dutch sorts. The largest plants and the largest blooms (5 in. across) are borne by the English Hybrids which bloom in July.

SITE AND SOIL: Well-drained, light soil is essential – chalk or lime is desirable. Thrives best in full sun.

PLANT DETAILS: See above.

PROPAGATION: Divide bulbs after foliage has died down – store until planting time in autumn.

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