Ground rules

3rd August 2001 at 01:00

Expert advice from 'Gardening Which?' by Rosemary Ward

When you cultivate a garden it's not just plants and flowers you'll become familiar with, but a whole company of minibeasts. We all love to see butterflies - but don't their caterpillars do a lot of damage? And what about spiders, beetles and worms - should we love them or loathe them? Learning about the creepy-crawlies that share our plots can make us better gardeners, and greatly enrich the whole gardening experience.


If four children stand in a ring, they could be standing on 500 earthworms, as most soils contain between 150 and 850 of the invertebrates per square metre of surface area. Earthworms play a crucial role in soil fertility, opening it up to air, water and root penetration, and breaking down dead plant material to release nutrients back into the earth. They come in many shapes and sizes, from the small stripey brandling, denizen of compost heaps and popular with fishermen, to the common earthworm, which can reach a length of 30cm and burrow two metres down. Worms can live up to two years, but don't cut them in half - at best, only one half will survive.


Britain is home to more than 4,000 species of beetle, ranging from the giant stag beetle at 50mm long to tiny rove beetles that measure less than 1mm. The great majority do no harm in the garden, though a few, such as vine weevils and lily beetles, are serious pests. Some, including aphid-eating ladybirds and slug-eating ground beetles, are a positive help. Ladybirds come in many varieties - red with black spots, black with red spots, yellow with brown spots and so on, and you should be able to find several species in the garden. Ground beetles are fast-moving, long-legged, and black or dark brown. Encourage them with flat stones or wood for them to hide under.

Bees Without bees, Britain's farmers would be pound;200 million poorer. This is the estimated value of the crops they pollinate, and it's not just honey bees, but stripey bumble bees and small, solitary bees that perform this valuable role. Bees also pollinate the strawberries, apples and runner beans in our gardens and rarely sting unless provoked. We can attract them with flowers containing lots of nectar such as grape hyacinth and flowering currant in spring; buddleia, cotoneaster, hebe, marjoram, mint and thyme in summer.


Little Miss Muffet did exist. Her name was Patience, and her father wrote a book about insects, worms and spiders that was published in 1658. We need to be braver than Patience, as spiders are fascinating and useful - they catch lots of garden pests. Each web-spinning species produces its own design, but many don't spin webs. Crab spiders can be yellow, white or pink, and hide in flowers ready to pounce on unsuspecting visitors. Wolf spiders ruthlessly hunt for prey on the ground, but they make devoted mothers, carrying a white silk egg sac, and later the spiderlings, around with them.

Slugs and snails

The gardener's most hated pest, the slug, can be very damaging, eating a wide range of plants above and below ground. Interestingly, bigger slugs do the least damage, preferring dead plant material - it's the smaller ones that cause most havoc. Snails, protected from drying out by their shells, are adventurous climbers and can be seen atop tall plants or in window boxes. Slug pellets are cheap and effective, but indiscriminate use can have a devastating effect on wildlife. Most other commercial control methods are expensive, although the absorbent mineral Snail Ban can be very effective. Home-made barriers such as rings cut from plastic drinks bottles are also worth a try.


Only two butterflies, the large and small white , develop from caterpillars that eat garden plants - in this case cabbages and other brassicas, plus nasturtiums. Moths are responsible for most caterpillar damage round the garden, but this is unlikely to be severe unless large numbers are feeding together. Keep caterpillars off crops with insect-proof mesh and, where necessary, pick them off ornamental plants and put them on the bird table.


Commonly known as greenfly or blackfly, aphids can also be yellow, pink or brown. They can build up in large numbers and damage young growth on flowers and vegetables as well as producing sticky honeydew which attracts black sooty mould. They also spread plant viruses. Finger and thumb make a quick and effective control, otherwise try a well-aimed jet of water or a contact insecticide - but make sure you read the instructions first.

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'Gardening Which?' members have access to free factsheets on a wide range of topics, plus a free advice service. Its magazine is packed with inspiration and practical advice.

For a free trial, tel: 0800 57 57 57. You'll receive three free magazines, a guide to member services, two classroom wallcharts on poisonous plants and pond wildlife, and, to keep you company in the garden, a pocket-sized radio with earphones. (To allow you to subscribe once your free trial ends, payment details will be requested when you take up this offer.) Peat-free paradise: Doune pupils in the bog section of their productive and multi-functional garden Photograph: Ashley CoombesAtom Germination of wild flowers has proved patchy. But successes have included the dainty Scottish primrose

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