Duncan Coombs answers your gardening queries
PUBLISHED: 14:13 20 March 2013 | UPDATED: 21:21 05 April 2013
Duncan Coombs answers questions about a month of unpredictability in the garden
April is a capricious month. Spring is with us, but winter and frost can return in an instant, while some days feel as summer is near. Gardeners beware, this is just this stop and start pattern that so many of our garden plants from foreign climes dislike so much.
So much has been written about herbaceous perennial and the wonderful naturalist displays one can have in late summer and autumn, but my herbaceous border looks bare and uninteresting right now. Help!
Spring flowering bulbs can help tremendously here, but carefully selected early flowering herbaceous plants, plus a few lesser known bulbs can also give colour and interest from their flowers and foliage until the main herbaceous stalwarts open up.
Persicaria bistora Superba, a selection of our native common bistort, several cultivars of Brunnera macrophylla and the many species and cultivars of Pulmonaria (lungwort) produce flowers for spring and generous foliage for later ground cover effect. All three genera prefer a moist soil and in the average border the addition of extra organic matter at planting or a position in part shade will give the best results.
Thermopsis rhombifolia var. montana is a slightly more unusual herbaceous perennial producing bright yellow lupin-like flowers in spring and early summer. Among bulbs Camassia and Ipheion are two genera containing pretty plants for late spring. In particular I would recommend Camassia Lady Eve Price growing approximately 50cm tall with electric blue flowers and Ipheion uniflorum Charlotte Bishop growing only 15-20cm tall and producing very attractive star-shaped pale pink flowers.
I have a bare wall that faces east. The site is rather cold and exposed and space is rather limited. I would like an attractive spring flowering climber. Does such a plant exist?
The site you describe certainly is rather challenging: cold windswept and with the added problem of early morning sun which is so damaging after frost in the spring! Fear not, Clematis alpina and Clematis macropetala and their cultivars thrive under such conditions and in my experience only grow up to about two metres in height. In addition, after flowering you will have the added attraction of feathery seed heads and no pruning is necessary.
A Cotswold stone trough has been given to me as a retirement present. My work colleagues say they expect to see a riotous spring display of alpines this time next year and up until now I have not been a keen gardener. Can you offer any advice?
What generous friends you have, such items do not come cheaply these days! Their request for a good display next year is easily achievable and planting and maintaining such a garden feature should provide you with a satisfying hobby. Place the trough in an open and sunny position. Ensure the trough has adequate drainage holes in its base, place a layer of broken clay pots or other coarse material as a layer in the base and then fill with an open, gritty compost. If you are unsure about preparing such compost some garden centres sell appropriate mixes.
The choice of plants you can then grow is the enormous, but the plants themselves should ideally be small and compact. For a display in late spring I would recommend plants from the genera Phlox, Primula, Pulsatilla, Saxifraga and Thymus. Once you catch the Alpine Bug as you surely will, you could subscribe to the Alpine Garden Society whose members and staff will be only too pleased to help you further as you progress to growing some of the more challenging true alpine plants.
Royal Horticultural Society members can get free advice from Duncan Coombs, at Pershore College, on Mondays from 9am to 4.30pm. Personal visits by appointment. Advice line: 01386 551145