Companion planting is an organic method of maintaining a natural balance in your garden, aiding pollination and keeping pest numbers down.
Common plant combinations include growing nasturtiums to deter aphids from attacking your beans, and planting alliums around carrots to ward off carrot root fly.
Most companion plants are strongly scented and confuse pests looking for their host plant. Others attract beneficial insects, such as ladybirds and lacewings, which prey on aphids.
Discover 10 companion plants to grow.
The strongly scented leaves of mint, Mentha spicata, confuse pests of carrots, tomatoes, alliums and brassicas, and deter flea beetles. But grow it in a pot, or it could smother your crop.
Bronze and green mint foliage
The garlic chive, Allium tuberosum, is a hardy perennial with white star-shaped flowers. When planted alongside carrots, its strong scent confuses and deters the carrot root fly, which can normally smell carrots from up to a mile away.
Star-shaped, white garlic chive flowers
Lavender, Lavandula angustifolia attracts a range of pollinators, including bees, butterflies and hoverflies. Its strong scent can also deter aphids. Plant with carrots and leeks to confuse pests.
A mass of mauve lavender blooms
Wormwood, Artemisia absinthium, is a strongly scented herb that can deter aphids and flea beetles from attacking neighbouring plants. Its yellow flowers attract hoverflies, lacewings and ladybirds, which prey on aphids.
Silver foliage and yellow flowers of artemisia
The marigold, Calendula officinalis, repels whitefly from tomatoes and can lure aphids away from beans. It also attracts beneficial insects, including ladybirds, lacewings and hoverflies, which prey on aphids.
Lemon yellow calendula flowers
Sage, Salvia officinalis, is strongly scented and will confuse pests of brassicas if planted alongside them. Its blue flowers attract bees and hoverflies, which also pollinate crops.
Purple and green sage shoots
Borage, Borago officinalis is an attractive plant with hairy leaves that have a slight cucumber flavour. Its delicate blue flowers are a magnet for pollinators, such as bees, butterflies and hoverflies, which pollinate crops. If planted nearby, borage can prevent attack from tomato hornworm and is said to improve the flavour of strawberries.
A blue borage bloom
Thyme, Thymus vulgaris makes a good companion plant for roses, as its strong scent deters blackfly. A tea made from soaking thyme leaves and sprayed on cabbages can prevent whitefly.
Tiny mauve thyme flowers
When planted with French and runner beans, the nasturtium, Tropaeolum majus, acts as a sacrificial crop, luring aphids away from the beans. Its attractive flowers help attract beneficial insects, which prey on aphids.
A yellow nasturtium bloom
If left to flower, fennel, Foeniculum vulgare, produces attractive yellow blooms that attract hoverflies, which prey on aphids.
Yellow fennel flowers
Kate Bradbury says
Borage is a particularly useful plant for wildlife. Studies have shown that its flowers refill with nectar every two minutes, making it a great choice for a small wildlife-friendly garden.