CHELSEA FLOWER SHOW 2008

Against all odds - plants for difficult conditions                     
By Andy McIndoe

Nearly all gardens have difficult situations: hot, dry sunny borders where the soil turns to dust in summer, cold wet corners where water lays in winter, or perhaps the whole garden is buffeted by wind or salt spray.  When trees and hedges mature growing conditions alongside them change because these large woody plants steal light and water from weaker subjects. In these conditions you need plants that can survive against all odds whilst maintaining their appearance.  

The main problem with our changing climate is that plants have to be able to withstand extremes: periods of drought and then spells of excessive rainfall.  Good drainage is essential, coupled with good soil condition, enabling the ground to hang onto water and nutrients whilst maintaining air space.  We need to encourage roots to go deep, and to insulate the soil against the heat of the sun and the drying conditions of the wind. Stone and gravel, in the form of scree are effective at achieving this insulation. 

To cope with drought think Mediterranean and aromatic: lavender, sage, thyme and rosemary all like hot dry conditions and produce aromatic foliage, great for summer barbecues. They produce their most fragrant foliage when grown on dry, poor soil and their flowers are attractive to bees, butterflies and pollinating insects.

Silver foliage subjects are well adapted to cope with drought.  Fine hairs protect the surface of the leaves preventing water loss and their light, bright colour reflects the light.  Santolina chamaecyparissus, Brachyglottis ‘Sunshine’ and Helichrysum italicum ‘Korma’ are all classic examples of silver foliage plants that cope with drought and come through the wet of the winter surprisingly well.  Convolvulus cneorum is a favourite dwarf shrub with silky silver leaves and white trumpet shaped flowers throughout the summer.  It is fabulous for a patio pot and needs much less watering than many bedding plants. It flowers for longer too!

Sun roses, cistus are compact evergreens that need little care and delight with a spectacular display of shimmering pink or white blooms in summer. Cistus ‘Sunset’ has woolly foliage and a compact habit. The bright magenta flowers sing out against silver-leaved companions. Cistus ‘Thrive’, with small dark green leaves and white, golden-eyed flowers is one of the toughest but also one of the daintiest.

Elaeagnus ‘Quicksilver’ is light, airy and elegant with pale silver leaves arching branches.  It is a wonderfully bright and beautiful background plant that shows off anything planted in front or alongside it. ‘Quicksilver’ is always a Chelsea showstopper and tolerates the driest, poorest soils. Elaeagnus x ebbingei is a large-growing evergreen shrub, superb as a structure plant or a windbreak.  It can be pruned to control its shape and size and makes a wonderful hedge on an exposed site.  The silver-backed leaves are not its only feature. Rabbits leave it alone and tiny cream flowers fill the garden with scent in autumn. 

Escallonias have similar properties to elaeagnus but with the advantage of pretty pink, white or red flowers that shine against their dark green leathery leaves. They respond well to clipping and shaping and the dwarf variety Escallonia ‘Red Dream’ makes a wonderful subject for a cloud bed or low cloud hedge when combined with small leaved Hebe ‘Sutherlandii’, trimmed box and santolina.

Palms, cordylines and phormiums may look exotic and tender but they are tough customers that stand up to winter cold as well as summer drought.  Phormium ‘Tricolor’ and Phormium ‘Cream Delight’ offer a lighter, brighter alternative to the purple leaved varieties. Their cream and green sword shaped leaves provide contrasting form to tough ground cover subjects such as vincas and hederas.

They also look good and will thrive when planted in an area of gravel or stone chippings. This surface is an excellent alternative to grass in a small space; it is maintenance free and there is no mowing to do! Add interest with creeping thymes, sedums and sempervivums and dwarf bulbs for early spring colour.

Those gardening on heavy clay can make gardening easier by the addition of ample sharp grit and well-rotted farmyard manure and garden compost.  This is a fertile soil and even if conditions are wet there are survivors: Cornus alba, Cornus sericea and Cornus sanguinea varieties grown for their colourful stems will thrive here as will willows and most alders.  The lovely Sambucus ‘Black Lace’ with its purple-black feathery foliage and Sambucus racemosa ‘Sutherland Gold’ are two fine foliage plants that will provide colour throughout spring summer and autumn on heavy, wet soil.

When gardening in situations where the chance of plants thriving seems to be against all odds, look to those reliable familiar subjects that are widely planted because they work.  Viburnum davidii, Euonymus fortunei, Euonymus japonicus, Vinca minor, Sarcococca confusa, Hedera helix to name but a few.

The Hillier Manual of Trees and Shrubs and The Hillier Gardener’s Guides are packed with suggestions for plants that will succeed in a variety of situations from dry shade to waterlogged soils.

All are available from Hillier Garden Centres or via our online shop www.hillier.co.uk.