Hardy herbaceous perennials continue to prove popular sellers at the garden centres.
These are plants which die down to ground level in the autumn, survive over the winter and grow back again in
They are especially suited to smaller gardens and their diversity makes them suitable for all aspects and soils. Early flowering perennials can be combined with spring flowering bulbs to produce masses of colour. Those which naturally grow in woodlands will tolerate a little shade and can be used with hardy ferns to produce colour in garden areas which don’t get sun for most of the day. Many also provide effective ground-cover, helping to keep weeds in check.
The perennial forget-me-nots or brunneras are aptly named. They produce pale blue flowers in April and May and make ideal ground cover, as they seldom grow above 18ins/45cm tall. There are varieties with variegated leaves such as Brunnera macrophylla ‘Variegata’ which has large, white-edged heart-shaped leaves. ‘Jack Frost’ is a real stunner. Its leaves are silver-grey with a network of green veins. These are easy plants for shady places, even under leafy trees.
Pulmonarias are known by lots of common names, including “lungwort” and “soldiers and sailors”.
Under trees and shrubs they too are ideal ground cover, growing to about 12ins/30cm high. When suited, they will quickly spread and will seed themselves to produce new plants. Most varieties produce their clusters of trumpet-shaped flowers in April and May. Amongst the best blues are ‘Beth Chatto’ and ‘Highdown’, which also have attractive silver mottled foliage. ‘Redstart’ has deep rosy-red flowers; ‘Sissinghurst’ is a free-flowering white variety.
The “Dutchman’s Breeches” or “Bleeding Heart”, Dicentra spectabilis, is an old favourite which grows best in light shade. Its deep pink flowers are borne on arching stems about 3ft/90cm tall.
There are lower growing dicentras which also make good weed-supressing ground cover. ‘Bacchanal’ has deep red flowers about 16ins/40cm tall over fresh, attractively divided foliage. ‘Pearl Drops’ has a winning combination of nodding white flowers and blue-green ferny foliage.
Euphorbias are some of the easiest perennials for shade. The woodland spurge Euphorbia amygdaloides robbiae is a tough plant for tough spots, even tolerating dry shade. It bears typical spurge flowers in sulphur and lime green in April and May and grows to about 12ins/30cm in height.
It is the parent of a hybrid Euphorbia x martini which is taller, around 30ins/75cm and evergreen in most winters, when the deep green leaves turn red. It has large heads of green leaf-like bracts with a red centre. Like all euphorbias, it has white sap which you should avoid getting on your skin.
Hardy container- grown perennials can be planted now. Prepare the soil in the usual way by removing weeds and adding organic matter such as manure, leaf mould or compost. A feed with a general fertiliser will help them establish and keep them watered if the weather is dry. If you’re growing these perennials under trees, they are best watered in dry summer weather. They can be propagated by dividing clumps either in the autumn or in February and March before growth begins.
Jobs for the month
April is a busy month. The clocks went forward at the end of March, daylight hours are noticeably increasing, and, weather permitting, we can enjoy and work in our gardens during the evening.
Mulch soil to keep weeds in check and conserve water.
Prune early flowering shrubs such as forsythias and flowering currants after they have finished flowering
Grass is now growing and lawns need cutting. For the first few cuts of the season set the mower blades at a height of around 1inch/2.5cm.
As the soil warms, weed seeds will begin germinating. On sunny days these can be controlled with a hoe, still the greenest way to weed, and good exercise too.
Warming soil also means that vegetables such as early peas, lettuce and broad beans can be direct sown and first early potato tubers planted. At Clumber we are growing about half a dozen early potatoes including ‘Accent’, ‘Rocket’ and ‘Duke of York’.
Remove the faded flower heads from early spring flowering bulbs.