Gardening for Butterflies

Many of us try to attract butterflies by planting nectar sources, like buddleia, in our gardens. Planting flowers raises an expectation which often leads to the question, "Why don't I see many butterflies?". There are several reasons, but the most important is that nectar sources simply retain butterflies which would otherwise fly straight through your garden. Nectar sources alone do not increase the numbers of butterflies.
Unlike bees that really benefit from extra nectar sources (as all the stages of their life cycle feed on nectar), butterflies only use nectar in the adult stage. Every adult butterfly spent weeks feeding as a caterpillar. Unless the plants that caterpillars need are growing in or near your garden, you will not see the adults.
A solution that is proven to work is to grow the plants that caterpillars eat and which also have attractive flowers to retain the adults when they emerge. Seeing butterflies that you know bred and fed as caterpillars in your garden, gives a real sense of achievement, just as seeing young birds from a nest in your garden.
It is even possible to grow plants that serve the dual purpose of feeding the caterpillars, with their leaves, and the adults with their flowers.
Some planting suggestions for various areas of the garden are listed below.
Finally, don't forget to submit your garden records, either during or at the end of the season.
Peacock butterfly on blackthorn flowers, which provide an excellent nectar supply early in the year. The leaves are the foodplant of several species of garden moth.
Six-spot Burnet moth caterpillar, which feeds on Birds-foot Trefoil.

Plants for long grass areas

Almost every garden has a patch of grass that could feed the larvae of nine butterfly and up to 40 moth species.
The most useful thing is to leave a strip of grass uncut until October. This works best if the strip is wider than 75cm/2.5 ft, in the sun and alongside a hedge or fence (to act as a wind break). There are various plants to grow in both the longer uncut grass and the shorter mown parts of the lawn. A really helpful plant to put in the long grass strip is Yellow Rattle (Rhinanthus minor). Although no butterfly caterpillars eat its leaves (Grass Rivulet moth caterpillars do), Bumblebees love the flowers and, more crucially, it parasitises the grass around it, making the turf less dense, which assists other plants to thrive. Yellow Rattle will not grow out into a lawn, as mowing destroys it. Several of the other plants suggested are invasive and removing their flower heads before the seeds are cast will help control their spread around the garden.

Plants for short grass areas

Mowing in spring to reduce grass length is helpful, but after May it is best not to mow until September. Cutting 1m/3ft wide paths through the grass area will increase butterfly and moth numbers more successfully than having all short, or all long, grass areas. You should always have some longer grass to act as shelter for the adult butterflies and moths. Well drained areas will host more caterpillars than damp ones.

Plants for borders and containers

In addition to the plants listed for use in long and short grass areas, there are plants which will do well in borders and in pots, but struggle in a grassed area. It is worth considering the amount of sun they will get before positioning them, and how you will group the plants. A group of similar plants will be more likely to attract egg laying females than individual plants spread around the garden.
Many caterpillars will thrive in a semi-shaded spot but some will need to be in full sun, or full shade. Pots not only allow the growing of plants in spaces with no soil, or with a different pH to the local soil, but also the movement of the plant during the year, including bringing them under cover for the winter. Plants with very invasive roots (e.g. nettles) can be restrained inside pots.

Plants for hedges and woodland edges

Hedges and, in some gardens, woodland edges, are very helpful to butterflies and moths. They can provide foodplants and give shelter from intense sun, wind and rain and in winter, frosts. They provide places for the caterpillars, pupae and adults to hide away from predators and parasites. The tallest plants in the hedge, or stems protruding from it, may well act as sites where adults can congregate to find mates and, of course, many of the hedge plants, on whose leaves caterpillars feed, also have flowers with nectar, and can produce fruits and nuts for a range of wildlife.
The best hedges are 3m/10ft tall and at least as wide. They should not be trimmed to produce a vertical edge, but have small bays and promontories as various species in the hedge grow at different rates. The benefit of the hedge will be increased if a 0.7m/2.5ft wide strip of uncut grass borders its base.

Large Trees

If you have the space (and you will need plenty!), various large tree species will provide food for as many moth caterpillars as the plants listed in the other sections. Trees have been shown to bring more wildlife to an area than any other single feature, even ponds.
It is not a good idea to plant a tree species capable of growing to 5m/16ft near domestic buildings and trying to restrict its growth with occasional pollarding. The roots can do extensive damage to pipes and foundations. However, there are places where larger trees are suitable and very productive. As with smaller plants, it is more useful to have a group of the same species than have a single tree. So, take account of those within 50m/160ft but outside the garden.