As spring arrives and plants come to life, gardeners often fight a losing battle against caterpillars munching on their cabbages.
Traditionally, advice to gardeners about caterpillars was how to get rid of them and plug unsightly holes in plants. But the Royal Horticultural Society (RHS) and Wildlife Trusts are calling on Britons to take a lax approach to killing caterpillars in order to sustain the moths on which many of them grow.
For particularly prized plants, the RHS recommends a pesticide-free approach, including manual removal, physical barriers and pruning.
Moth populations are plummeting, charities have warned, and many of the UK’s 2,500 species are at risk, with their numbers declining by 33% since the 1960s. This is due to factors including habitat loss, climate deterioration and pollution.
Helen Bostock, RHS wildlife expert, said: “Moths have long played second fiddle to butterflies in the garden, but understanding their value and needs, and those of their very hungry caterpillars, can support their recovery and help create a garden rich in biodiversity.”
Not only are they important in their own right, but they are also an important food source for other at-risk wildlife, such as birds, mammals and larger insects.
Some species of caterpillars wander around the garden and eat everything in sight, while others are specialists. The RHS has encouraged gardeners to appreciate caterpillars in their garden. While some are large, green and easy to spot, others are camouflaged and look like twigs, bark or even bird droppings.
They transform into striking moths, including the pink and green elephant hawk moth, the lunar hornet moth disguised as a wasp and the contrasting red, cream and black Jersey tiger moth, which is becoming more common in the UK as the climate warms.
Caterpillars need a lot of energy to transform into a moth. The RHS has asked gardeners to “allow nibbling on vegetable and ornamental crops”.
The charity also suggested planting native trees and shrubs enjoyed by a wide range of caterpillars, including willow, honeysuckle, foxglove, verbascum, comfrey, marjoram, strawberry, sweet william, sweet rocket, tobacco plant, jasmine and white campion.
Vicki Hird, insect expert at The Wildlife Trusts, said: “The moths have an impressive name and are naturally beautiful. The green, black and white daylight wonder appears to have been exquisitely painted by an artist, and the white stoat appears to be casually wrapped in a coat of black spots with a warm ruff of fur.
“No wonder the French call moths ‘butterflies of the night’. Even small brown moths can have wonderful, intricate markings. Making a simple moth trap is a wonderful way to enjoy these incredible creatures up close before releasing them back into the wild.”
Caterpillar friendly planting
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Foxgloves: These pretty plants are food for several moths, including the lesser yellow underwing (Noctua is coming), angular shadow moth (Phlogophora meticulosa) and setaceous Hebrew character (Xestia c-nigrum).
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lady’s handjob: This native wildflower with foamy yellow flowers provides food for the hummingbird hawkmoth (Macroglossum stellatarum), elephant hawk moth (Deilephila elpenor) and hawkmoth (Hyles galii).
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mullein: These tall, drought-resistant yellow plants are enjoyed by the brightly striped caterpillars of the mullein moth (Cucullia verbasci).
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Mint: This provides food for the mint moth and the beautiful plume moth. It is also loved by bees.
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hedges: If you have space, a mixed native hedge planted with hawthorn (Crataegus monogyna), blackthorn (Prunus spinosa), hazelnut (Coryllus avellana) and rosehip (dog rose) provides food for a multitude of caterpillars.
