Barrenwort, Epimedium

Spring and early summer flowering epimediums perk up the ground beneath trees and make excellent ground cover. The new foliage is often a shade of coppery red, with a lively show of flowers from yellow to rich ruby.

Recommended varieties

The main choice is between the evergreen and deciduous kinds (the latter have rich green leaves in summer which turn copper and gold before falling). Though most are good spreaders, some by up to 60cm (2ft), there are more manageable kinds which spread by only half as much.

Evergreens

The following varieties are extremely useful because they keep down weeds which shoot up in mild weather between autumn and spring.

E. x perralchicum E . x perralchicum : produces sunny yellow flowers on tall stems above the glossy green foliage which is initially bronze. Plants retain most of their foliage throughout the year and make tough, effective ground cover, spreading up to 60cm (2ft). The Royal Horticultural Society has given it its prestigious Award of Garden Merit (AGM).
E. pinnatum subsp. colchicum E. pinnatum subsp. colchicum : the small spring flowers, sometimes with long spurs, have four, flat, bright yellow petals and sit well above the clump of dark green, heart-shaped leaves; spreads up to 25cm (10in). The Royal Horticultural Society has given it its AGM.
E. stellulatum 'Wudang Star'; provides clusters of star-shaped white flowers, and was discovered growing in the wild by Roy Lancaster in 1983; spreads by 25cm (10in). Sold by several specialist nurseries but deserves to be much more popular.
E . x versicolor 'Sulphureum' ; a semi-evergreen variety, it produces sprays of lemon-yellow blooms making a fine display in a shady corner, and spreads quickly even in fairly dry shade up to 1m (3ft).

Deciduous

E. grandiflorum : very popular because of the sheer impact of its large colourful flowers and long projecting spurs. It has two outstanding forms, 'Rose Queen' (with new, deep bronze-purple-flushed leaves and pink flowers) and 'Lilafee' (purple-tinged new leaves and light purple flowers). The creamy, white-flowering 'Nanum' is about one quarter the size, making it a good candidate for an alpine trough or container; spread: 30cm (12in). The Royal Horticultural Society has given it its AGM.
E. x rubrum E . x rubrum : widely available and one of the best-known kinds, with rich bronze foliage tints appearing in spring and again in autumn before the leaves die back. The colouring makes an excellent contrast against the emerald green veins. Sprays of red flowers with short yellow spurs appear just above the new leaves in April. Try growing them with trilliums and erythroniums in a border packed with cooler shades; spread: 30cm (12in). The Royal Horticultural Society has given it its AGM.
E . x youngianum : an extremely popular pure white form which quickly brightens up dull corners, and one of the daintiest Japanese epimediums. The new spring foliage can be wonderfully colourful, and the heart-shaped leaflets form a neat, slowly spreading clump. 'Merlin' is a good alternative with mauve flowers opening above the emerging purple leaves; spread: 30cm (12in).

Growing tips

Site and soil preferences

Epimediums virtually look after themselves in well-drained, humus-rich soil. This should be enriched before planting with well-rotted compost or leaf-mould.

Mulching

Apply a thick winter mulch of compost or leaf-mould to lock moisture in the ground, and a sprinkling of fertiliser to keep plants happy through the year.

Frost damage

Prolonged cold and frost can damage all epimediums when they emerge in the spring. The leaves normally grow back, but the flowers will probably be lost for that year. One solution is to keep the old growth as protection for the new, tender flowers and foliage. However, it may obscure them, and the old growth can then be extremely difficult to remove once the new growth appears. A second option is to prune the plant right to the ground in late winter. This method is a lot quicker and ensures that the flowers are seen at their best, but does run the risk of frost damage. To overcome this, a mulch of bark or compost sprinkled over the plants after they have been cut back will help protect the new growth.

Excess spread

Evergreen varieties that have spread thickly do not need cutting back. However, if they are encroaching further than desired, slice off any excess growth with a spade.

Renovating old plants

When they are deteriorating in leaf size or flower power it's best to dig them up every three or four years, dividing and replanting the sections in improved soil.

Growing in pots

Planting epimediums in containers is a novel way of growing them, especially the newer types with larger flowers. The pots can be brought into a glasshouse or cool conservatory when coming into flower, providing fun colours. This also way protects the blooms and foliage from frost damage and cold winds.