Provided that they have been properly planted, your climbers and wall shrubs will grow with very little trouble. But the addition of some fertilizer in the spring can make a tremendous difference to the rate of growth and the quality of flowers or fruit. Bonemeal is ideal for this purpose; it is high in phosphorus, the essential element for flowers and fruit, and it also includes some nitrogen, which will encourage the growth of leaves. If you had too much nitrogen you would end up with foliage at the expense of flowers, but in bonemeal the balance is just right. Scatter the bonemeal round the base of the plant and fork it in lightly, taking great care not to spear the roots or the stem.
To keep the plants growing well in summer and to keep their roots cool— an essential item to watch if you are growing them against a south-or west-facing wall— give them a good mulch of compost, moss peat, spent mushroom compost or shredded bark. A layer of this on the soil round the plant will work wonders, helping to keep moisture in during a period of drought, too. It has another use: it keeps weeds from springing up round the plant. Farmyard manure or home-made compost will give the plant the nitrogen which it needs at this time. If you are using an inert mulch such as shredded bark or peat, give your plants a feed of a fertilizer with a high proportion of nitrogen as well.
During the hot summer months your plants would appreciate an occasional spray to clean their leaves: this applies particularly to evergreens in town conditions. Regular misting, if there is a long dry spell, will also keep away the red spider, a pest that normally only attacks the plants outdoors in drought conditions. Your climbers will need help during a dry summer spell, so do not forget them when you are watering the garden.
But remember that it is better not to water at all than to give a token amount: water that barely penetrates the surface of the soil does more harm than good. It encourages the roots to come up towards the surface in search of the moisture, where they will almost certainly die off in soil baked by the hot sun.
Groom your wall plants from time to time. Evergreens in particular ‘collect’ dead leaves and all sorts of decaying material in their branches, flowering climbers look unsightly if the blooms are left on the plant in large numbers as they die off. The formation of seed pods de- prives the plant of food and energy which would be better directed towards new growth.
When winter comes, plants that are not quite hardy may need special attention. Do not allow the roots of these plants to ‘sit’ in heavy, waterlogged soil if you can help it, for they may suffer from damage by frost. Put a deep mulch of straw, spent mushroom compost or similar material round the base of the plant and cover it with heavy duty plastic: the roots will then get some protection and are less likely to become waterlogged.
Tender evergreens may suffer from frost-burn, and the only way to avoid this is to cover them in sacking, nailing it to the wall or, for a shrub, wrapping it round them.
Climbers in tubs are especially vulnerable to cold weather, since the frost is much more able to reach their roots. Wrap the tubs in sacking, or several layers of newspaper covered with polythene, to keep them as warm as possible; better still, move them to a sheltered place.
