The Moths in Your Garden

A huge upsurge in interest in the moths that visit or live in our garden has come about in the last ten years or so, as people have begun to realise how beautiful many moths are, and how many species we can see in our gardens.  Compared with 60 or so species of butterfly in Britain, the number of moths is huge – around 2,500 species.  A well-managed organic garden could expect visits from several hundred of these; indeed at least 300 species have a preference for garden habitats.  Some moths will visit for nectar and others may lay their eggs on the leaves of trees, shrubs and wildflowers that may be around or in our gardens, which means that we can play an important part in their conservation.

As you might expect, the environment in and immediately around the garden is particularly important if you hope to see a good variety of moths in your area.  Although they are winged insects and some species will fly long distances (some are migrants in much the same way as a red admiral or painted lady butterfly) many more have a narrow range and may live out their whole life cycle around a locality that provides them with their larval food plants.  Having the right plants available is crucial to their survival.

For many people their first encounter with the moth family is as a child, when caterpillars can be fascinating and fun!  The brown hairy ‘woolly bear’ that many of us know, is the caterpillar of the garden tiger, a brightly coloured moth which is common and well distributed throughout the country with the exception of Shetland.  This species has mottled brown and cream forewings, perfect for camouflage, and bright scarlet under wings with dark spots.  Many moth species have brightly coloured under wings, which helps in their identification.  The caterpillars of the garden tiger feed on nettles and docks as well as some other herbaceous plants, so allowing these plants a bit of space can encourage these wonderful moths.  The ‘tigers’ are an attractive group and the scarlet tiger, a day-flying species often mistaken for a butterfly, has bright red under wings making it highly visible in flight.  In good years it may appear in gardens so look out for it in June and July when the male patrols his territory.

There are a great many beautiful species of these insects in a huge variety of colours and shapes.  Many are well camouflaged and some, such as the marbled green, which lays its eggs on lichens growing on tree bark, resemble the environment in which they live.  Other green moths, including the scarce silver lines and the lime hawk moth, are coloured to blend into a background of leaves, allowing them to roost safely.  More species, including the pink elephant hawk moth are brightly coloured, or some are shining white like the swallowtail moth or white ermine.  These fascinating insects come in all shapes, sizes and colours, as do their caterpillars.

So how can we encourage more of these beautiful insects into our gardens or provide a habitat for those that are around us?  Obviously what we grow is crucial as, like butterflies, moths use specific larval food plants.  However, moths can be much more adventurous and adaptable in their tastes and there are many species that use a wide range of herbaceous plants for their caterpillars.  ‘Weedy’ plants such as nettles, docks and grasses are used by many species, so a wild patch in the garden will be extremely beneficial to caterpillars.  Other very useful plants are native trees and shrubs, which means that a mixed native hedge is a moth magnet especially if a goat willow is included.    Many moth larvae feed on willow including two aptly named species - the sallow and the centre barred sallow - plus the puss moth, the eyed hawk moth and the white satin moth.  Other species feed on the leaves of hawthorn, blackthorn, dogwood and spindle.  The native birches are also food for a variety of moths including the lesser swallow prominent, scalloped hook tip and the gorgeous green large emerald.  Poplars and aspen support a range of species including the figure of eighty, named after the characters on its wings.

Providing nectar for moths is also an important consideration.  Not all adult moths feed, but those that do prefer nectar from night scented plants.  Evening primrose, night scented stock, red and white campion and honeysuckle are good nectar providers for moths, and tobacco plants can sometimes attract even large migrant moths such as the massive convolvulus hawk moth.  Buddleia is equally as good for moths as it is for butterflies.  A range of easy to grow wildflowers and cottage garden plants plus a Buddleia will go a long way to providing food for these insects.

The third consideration after providing food plants and nectar is how to manage your garden in the months when the moths are hibernating, usually as pupae or, with some species, as caterpillars.  We have already seen how a wilder patch of garden, where nettles, docks and long grass grow, can benefit moths by providing food for some caterpillars, but areas such as this can also be left well alone to protect the wildlife using them.  This will ensure that larvae and pupae are relatively undisturbed at all stages of their life cycle.  A wilder area  can be enhanced with more wildflowers – campions, foxgloves, mullein or dead nettle - to benefit yet more species and other invertebrates also.  Leaving herbaceous borders untouched during the winter months will also benefit moths.

It is inevitable that as you discover this group of insects you will want to find out more about them and possibly watch them in your garden.  Not all moths come to an outside light, but leaving on a light at dusk will attract a small range of species.  A bright lamp on an old white sheet on the lawn will give you an opportunity to see moths in more detail, as they will generally alight on the pale cloth.  If you really want to get involved, your own moth trap - a contraption that attracts the insects to a special bulb under which they shelter in safety – could be the next step.  Contact your local wildlife trust to find out if there are any moth-watching events in your area.  You will also meet the local moth experts this way – identification of moths can be very difficult!

Any gardener worth his salt is going to be a little bit concerned about encouraging too many moths into a productive fruit and vegetable garden.  Aren’t these insects going to lay their eggs and the caterpillars eat precious crops?  If you do have concerns about this it is worth remembering that moths and their caterpillars provide a huge amount of natural food for a great range of garden wildlife.  A vast number of caterpillars of moths and other insects are fed to young birds in the spring and about one quarter of a hedgehog’s diet is composed of caterpillars.  Bats also rely on moths for food.  By encouraging these insects you will be enriching your whole garden ecosystem and encouraging natural predators.   

For more information on moths The Field Guide to the Moths of Great Britain by Paul Waring, Martin Townsend and Richard Lewington  

published by British Wildlife Publishing



© Text and photographs Jenny Steel 2017