How to grow crocosmias

Val Bourne

Acclaimed gardening writer, Val Bourne, shares how to grow crocosmias, a beautiful addition to a summer border.

Crocosmias provide branching heads of bright, sunny flowers and strong sword-shaped leaves so they provide structure and colour in the sunny border. There are hundreds on offer. But they vary in flowering times, flower colour and stature.

They are all bred from South African species but despite this almost all of them are hardy and reliable in the garden - happily coming back year after year. The darker-leaved varieties tend to be less hardy, however.

Read Val Bourne's recommended crocosmia varieties to grow in the UK.

Where to plant

These South African plants really need full sun and good soil to perform well. In 2007 the month-long July deluge suited them very well and they flowered more prolifically in the following months - as did kniphofias. Both tend to get summer rainfall in their native habitat - followed by coldish winters.

Most crocosmias thrive once planted in a sunny position and they form a tight clump and produce a lot of flowers. But their habit varies greatly according to cultivar and your location. In warmer areas crocosmias tend to grow larger. But if space is limited plant a smaller crocosmia - as some of the taller ones need lots of space.

When to divide

A clump can usually be left undivided as the new corm forms above last year’s to produce a vertical chain of corms. This system ensures vigour is maintained from year to year as the old corms rot they feed the plant. If you do divide, do it in spring just as growth restarts.

Read our guide to dividing perennials.

Grow with...

Late-flowering shorter orange crocosmias are excellent with sun-seeking asters (like Aster x frikartii ‘Monch’ or Aster amellus ‘Violet Queen’) or heleniums. They can also be planted in front of late-flowering aconitums like ‘Arendsii’.

The taller ones look good among grasses and these include the willowy Molinia caerulea subsp. arundinacea Transparent and the soft, fluffy Pennisetum orientale.

Early flowering varieties (like the red ‘Lucifer’) can be used with deep-blue catmints such as Nepeta subsessilis.

Later-flowering, fiery varieties can be woven up through purple dahlias like the cactus-flowered ‘Orfeo’ to make a vibrant contrast.

If you're planning on growing crocosmias for a warm colour scheme, read our suggestions for red flowers, orange flowers and yellow flowers.

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