How to....make a butterfly garden
Butterflies are some of our most beautiful wild creatures. Britain has over 50 different types of butterfly, most of which have been recorded in Cornwall. However, many of these lovely insects are becoming rarer. The destruction of our hedges and woodlands, and modern agricultural techniques involving wide use of pesticides and herbicides, have led to the loss of wildflower meadows and the insects they support.
You can do your bit to help reverse this decline. You donŐt need a lot of space, but with a little knowledge and careful planning you can make your garden a suitable feeding - and even breeding - station.
Most butterflies are highly mobile and likely to find their way into any garden, and they will stay if there is something to keep them. Many people are under the impression that a butterfly garden has to be a wilderness of native plants. This could not be further from the truth. The butterfly has a few basic requirements and these can be met in many ways.
Warmth, shelter and food
Butterflies are 'cold-blooded' and need warmth before they can become active. Once mobile, they will seek out a sheltered spot in which to sunbathe and then find a nectar source. If all these requirements can be met in one place, you have created 'butterfly heaven'.
Site your butterfly garden in a sheltered, sunny spot. Extra shelter can be provided by planting shrubs and trees along the northern boundary. A hedge is better than a fence or wall in reducing wind. Privet, hawthorn, laurel and holly, if allowed to flower, will provide nectar too.
The best nectar plants
Butterflies need sugar-rich nectar from flowers which release it readily - not all flowers are suitable. You will need a selection of suitable species with differing flowering times to provide food for the duration of the period that the butterfly is on the wing - March to October. You will also need enough of each type to make an easily visible display that will give off enough scent to attract the insects into your garden.
A good early spring flower is aubretia - ideal for newly awakening butterflies that have hibernated over the winter. Honesty and sweet rocket fill in the late spring period from April to May. Later in the summer, a multitude of species is available, but red valerian, knapweed, marjoram, thyme, lavender and sweet scabious are amongst the most popular. Buddleia or 'butterfly bush' (only the mauve variety) is a must if you have the space. In late summer and autumn, ice plant, goldenrod and then michaelmas daisy give butterflies a last boost before winter hibernation.
Persuading butterflies to breed
Ivy provides winter nectar in case an unseasonal warm spell temporarily brings butterflies out of hibernation.Encouraging butterflies to breed is more complicated but very worthwhile. The female insect is very choosy about the types of plant she will lay her eggs on - different caterpillars like different food plants and they are usually native species.
The easiest to attract are the nettle feeders. Grow a patch of stinging nettles in a sunny, sheltered spot. It may be advisable to plant them in an old tub sunk in the ground to prevent them spreading. This could then attract small tortoiseshell, peacock, comma and red admiral. Caterpillars prefer young growth, so cut down half of your patch in late June or early July (remove any caterpillars first) to maintain young growth for the next generation of butterflies.
Changing your habits
Of course, all of this effort will have been wasted if you continue to use pesticides, as many that are designed to kill garden pests will also kill caterpillars. Think twice before you use them, and find out more about organic gardening techniques - e.g. dilute household detergent is effective against greenfly and blackfly and not thought to harm caterpillars or butterflies.
Don't delay - get out those seed catalogues or take a trip to the garden centre and start planning now!
This guide has been written by Sue Hocking, Conservation Officer of the Cornwall Wildlife Trust. If you would like more information on suitable butterfly nectar plants or larval food plants call the Trust on (01872) 273939.
Illustration from The Wildlife Trusts' Wildlife Action Pack