SEASONAL TIPS

Slugs and snails.

With the increased warmth and spring rains there will be a huge increase in the populations of slugs and snails that cause damage to plants. Killing slugs and snails using slug pellets is now discouraged by the Royal Horticultural Society, which argues that these gastropods have a useful role in any garden. Many slugs and snails are recyclers, feeding on decomposing dead leaves, dung and even dead animals. They also provide an important source of food for birds, beetles and reptiles. If you want to stop slugs and snails feeding on your prized plants:

• Try surrounding the plant with a copper ring or copper tape.
• Sink a glass jar in the ground with the lip just proud and fill it with beer to make it a beer trap.
• Hedgehogs, frogs, toads and thrushes all prey on slugs and snails so encourage them. Lay a flat stone in the border so thrushes can use it as an anvil.

Give your borders a tidy.

While the soil is damp it is a good time to lightly fork it over and pull out any weeds. Any plants growing across other plants can be lightly pruned into shape to keep them looking tidy. Don’t prune too hard or you may cut off this year’s flowers.

Remove frost-damaged shoots from shrubs:

Slightly tender evergreen shrubs like Choisya ternate (Mexican orange blossom) can be caught by the frost, so this month is a good time to tidy them up and remove any crossed or misplaced stems.

Spray roses:

Spray roses with a recommended fungicide to control black spot. This should be done at regular intervals as it is difficult to control once it takes hold. Also make sure you have collected any old leaves that are lying around the plants from last year as these are a source of reinfection. Also, check your roses for aphids and rub or hose these off as soon as you spot them.

A relatively new pesticide SB Plant Invigorator is now available from internet retailers. It controls a wide range of pests: whitefly, aphids, spider mites, mealy bugs and powdery mildew. It is a non-chemical insecticide with a physical mode of action (surfactant) on the target. It is safe to use on house plants and there is no harvest interval after spraying it on food plants. Pests do not become resistant to it.

Prune shrubs:

The best coloured foliage is produced on new stems, so there is good reason to prune hard this month. If you want to increase the size of the plant you can leave two or three shoots unpruned and these can grow on making a larger plant without compromising the colour. After pruning, feed with a general fertiliser and water in if the weather is dry.

Prune forsythias and chaenomeles after flowering. These shrubs put on a terrific show in the spring, on wood made the previous summer, so prune them for flowers next spring. When the flowers have gone cut back to 2 or 3 buds from the base. On more established shrubs cut out about a third of the older growth to the base of the plant. It will encourage new shoots to grow from the base.