Recognising Common Butterflies of Lowland Heath and Moorland

Why Heathland Butterflies Are Worth Knowing

Lowland heath and moorland are among the most distinctive habitats in the UK, but they are also among the most fragmented. Silver-studded blue, grayling and green hairstreak are three specialities that rely on these open landscapes, and each has its own foodplants, flight period and behaviour. Learning to recognise them is more than a pleasant pastime. It helps you judge whether a site is being managed well, and it can guide what you plant and leave undisturbed in your own garden, especially if you live near a heath or moor.

Silver-Studded Blue: Small, Scarce and Heather-Dependent

The silver-studded blue is a butterfly of lowland heath, sand dunes and occasionally moorland edges. Males are a vivid blue with dark borders; females are brown, often with a blue dusting near the body. The underside is the giveaway: grey-brown with a row of orange spots and, crucially, a scattering of silver-blue studs near the wing edge. Look for it from late June to August, with occasional late May records in southern England.

Its caterpillars feed on young heather, especially bell heather and ling, as well as gorse and bird's-foot trefoil. The species also depends on ants, particularly black garden ants and wood ants, which tend the larvae and pupae underground. This makes it vulnerable to heavy grazing, scrub encroachment and disturbance of ant nests. In a wildlife-friendly garden near heathland, encouraging heathers, gorse and bird's-foot trefoil in sunny, sheltered spots can help. Avoid disturbing ant mounds, and keep a little bare, warm ground for basking.

Grayling: The Sun-Basking Camouflage Expert

The grayling is a master of disguise. When resting, it holds its wings closed and tilts them towards the sun, casting a shadow that makes it look like a piece of bark or stone. The underside is mottled grey and brown with small eye spots and bands of orange. It flies from July to September, usually in a single brood.

Its caterpillars feed on fine grasses such as sheep's fescue, red fescue, bristle bent and marram grass. You will find it on lowland heath, coastal dunes, moorland and rocky slopes, always where there is plenty of bare, warm ground. In the garden, leave tussocky native grasses unmown through the winter and keep a few patches of bare soil or gravel. Avoid smothering every inch with mulch. A sunny, south-facing bank with fine grasses and occasional nectar sources such as thyme, marjoram or ragwort is ideal, provided livestock and pets are kept away from ragwort.

Green Hairstreak: The Green Jewel of Scrubby Edges

The green hairstreak is a small, lively butterfly with a brilliant green underside and a faint line of white dashes. It almost never shows its upperwings when settled, so the green is what you will see as it spirals around scrub. It flies from April to June, one of the first butterflies of the heathland year.

Its foodplants are varied: gorse, broom, bilberry, dogwood, buckthorn, common rock-rose and bird's-foot trefoil. This flexibility makes it a good candidate for gardens with acidic soil or a wilder corner. Grow bilberry in shade or dappled light, and allow gorse or broom to remain if you have space and local permission. On moorland, green hairstreaks often use young bilberry and gorse, so rotational cutting that leaves some young growth is far better than cutting everything at once.

Gardening for Heathland Butterflies: Practical Steps

• Plant native foodplants. Heathers, bilberry, bird's-foot trefoil, common rock-rose, gorse and broom support the caterpillars of these three species, as well as many moths.
• Leave tussocky grasses. Fine grasses such as fescues and bent are essential for grayling larvae. Mow paths only, and leave the rest long until late summer.
• Keep bare, sunny ground. Butterflies need warm places to bask. A gravel patch, a sandy bank or a few unmulched beds will do.
• Grow nectar for adults. Heather, bramble, thyme, marjoram, knapweed, oxeye daisy and lavender provide fuel during flight periods.
• Avoid pesticides. Insecticides and herbicides remove both caterpillars and the ants that some species rely on.
• Manage scrub rotationally. Cut gorse, broom or birch in sections, not all at once, so there is always young growth and shelter.
• Connect with local heath. If you live near a heath or moor, your garden can act as a stepping stone. Avoid invasive plants such as Rhododendron ponticum and cotoneaster, which spread onto open habitats.

Flight Periods at a Glance

• Green hairstreak: April to June, peaking in May.
• Silver-studded blue: late June to August, occasionally late May in the south.
• Grayling: July to September, peaking in August.
• Small heath: May to September, often in two broods.
• Small copper: April to October, in overlapping broods.

Watch for these dates shifting with latitude and weather. A warm spring can bring green hairstreaks out in March in southern England, while northern moorland colonies may fly well into July. Recording your sightings with a local butterfly group helps conservationists understand how these specialities are faring. Whether you manage a garden, an allotment edge or a patch of heath, the same principles apply: foodplants, shelter, sun and a gentle hand.