A garden that is good for wildlife is likely to be a stable ecosystem in its own right, integrated with the landscape around it and providing a diversity of micro-habitats within its boundaries. 

Such stability has advantages for you, the gardener, as well. A stable, diverse system is unlikely to be over-dominated by any one species or group of organisms. In practical terms, this means that you should have fewer problems with pest or weed species and be less prone to outbreaks of disease among the plants that you grow.

Working with nature should also reduce the amount of management work that you have to do within the garden. There are some guiding principles that can help as you attempt to develop your garden for wildlife.

Integrate with the landscape 

Which species use your garden will, in part, be determined by where your garden is located and which habitats surround it. Consider the nature of the landscape before you set about adding features to your garden. You may not be able to provide a feature that a particular species needs in order to breed, but you may be able to add a feature that supports the species if it happens to be breeding nearby. For example, the Gatekeeper butterfly does not usually breed in gardens because it needs rank grasses for egg-laying. While such micro-habitats are still to be found in farmland, often alongside hedgerows, nectar sources important to the adults may be missing. You can help by providing plants like Wild Marjoram Origanum vulgare, Common Fleabane Pulicaria vulgare or bramble Rubus fruticosus agg.

Provide plenty of choice

As gardeners, we are in the privileged position of being able to create an artificially high number of micro-habitats within a small area. A Blackbird, for example, may nest and shelter in your shrubs, feed on worms taken from your lawn, or bathe in your pond. Such features are surrogates for the naturally-occurring micro-habitats found within the woodland shrub layer and woodland glades.

Think about plant origins

The communities of plants in our gardens are likely to be rather different from those established in other habitats. A typical garden flora will almost certainly be composed of a mixture of native and non-native (alien) species, selected for a range of reasons not necessarily linked to their wildlife benefit. There has been a significant amount written about the benefits of using native species in preference to alien ones. However, in contrast to the plethora of advice derived from the notion that native plants are good and introduced ones are bad, there has been very little scientific research into this particular question. While there has been little direct comparison of native and alien species and their use by insects and other organisms, it would be wrong to say that alien plants as a whole have little or no wildlife value. Some will be of value, some will not be of value and some will be invasive and should be avoided altogether.

Consider flower form

There is an ever-increasing array of plant varieties on sale at garden centres and specialist nurseries these days, with new colour forms and structurally divergent cultivars of familiar plants for use in our gardens. Such cultivars may be very variable in their wildlife value when compared with ancestral forms. 

For example, the double-flowered cultivars of certain species have become popular because of their novel appearance and longer flowering season. However, these double cultivars have been shown to produce less seed and their unusual structure may also decrease their value to nectar-feeding insects.

The RHS Plants for Pollinators list provides a good starting point when considering which plants are of most value to nectar-feeding insects. However, it's important to bear in mind that insect lifecycles rely on a variety of food sources, not just nectar.