There are a number of things you can do to help create good conditions for butterflies in your garden. For example, the use of native plants and low impact gardening, avoiding pesticides, and encouraging areas of grassland to grow tall before mowing. More specific advice will depend on local factors such as the soil type and whether you are near existing populations of important butterfly species, but mostly gardens support the widespread common species and achieving conditions where these can thrive will create a nice environment for wildlife and you.
The amount you can achieve will also depend on how much time, money and effort you want to spend on creating the garden, and what other things you want the garden for. A large area of short regularly mown lawn will not benefit butterflies but if you can let most of the grass grow tall and just cut paths and seating areas in among it that would be good.
Most people think of nectar plants for butterflies, these are the flowers which the adult butterflies visit to collect nectar and this is when we see most butterflies, but in fact the most important part of their life cycle is the caterpillar stage, and providing the very specific plants and conditions for caterpillars is more important if you can do this.
Each butterfly species has a different requirement as a caterpillar, but there are two categories of plants which are particularly important – grasses and nettles. The standard grasses that are used for making lawns are generally not compatible with butterflies. The native species of grass which are most important are: Cocksfoot, Red Fescue and a few others including Yorkshire Fog. Nettles are not very popular in most gardens, but a big patch in a sunny corner will provide food for the caterpillars of our most attractive species: Peacock, Small Tortoiseshell and Red Admiral.
For nectar plants, almost all butterflies appreciate bramble flowers, and the fruits of Blackberries also provide food for butterflies in autumn. Flowering herbs are very useful, such as Marjoram, Thyme and Lavender. Meadow plants are very useful, particularly birdsfoot trefoil which also provides food for the caterpillars of Common Blue butterflies, but Kknapweed, Scabious and Dandelion are also useful for nectar.
Most butterflies like full sun and fairly low vegetation but some butterflies like more shade, and use shrubs and trees, so the design of the garden needs some consideration. Particularly useful shrubs are Holly, Ivy, Dogwood and Buckthorn or Alder Buckthorn, these species will support the caterpillars of Holly Blue and Brimstone, while also providing some additional nectar in some cases. If you have room for Oak, Elm and Sallow trees you may attract some more specialised butterfly species.
Things to avoid are the kinds of plants and shrubs which are most often seen in garden shops, these are often from other parts of the world and have no nutritional value to native butterfly species, and often the flowers are highly modified to look spectacular but provide little or no nectar.
Whatever you choose to do, the best of luck and I hope you get to enjoy more butterflies in your garden – it is a fascinating element to study. Learning the different species and what their habits and requirements are is a good way to get to know what you should and shouldn't be doing, and it can be a lifetime of study and pleasure! And do remember to submit your sightings on the Branch's sightings page.
Vince Lea, Branch Conservation Officer for Cambridgeshire.