Dig It – June Tips from the Secret Gardener

Elephant hawk-moth caterpillar

Hawk-moths include the biggest moths in the UK and they are named because of their size and aerobatic skill. There are 11 species resident in the British Isles, two of which - the Humming-bird and Bedstraw Hawk-moths - are also immigrants. Additionally, there are six further immigrants. Hawk-moths that you might find active in your garden at night include Elephant, Eyed, Lime, Poplar and Privet Hawk-moths whereas the Humming-bird Hawk-moth is day-flying.

You are likely to spot a Humming-bird Hawk-moth in the sunshine, hovering in front of flowers such as Red Valerian, Phlox, Lilac and Buddleia, sipping the nectar with its long proboscis.

Lime hawk-moth - Ben ColemanThe caterpillars feed on Lady’s Bedstraw, Hedge Bedstraw and Wild Madder and some of these may hatch and give rise to autumn adults.

Some adults do not feed, including the Eyed, Lime and Poplar Hawk-moths. However, Elephant and Privet Hawk-moths will feed from flowers. Nectar plants which attract these night-feeding moths tend to be pale-coloured, tubular and often scented, such as Honeysuckle, Jasmine and Nicotiana.

Hawk-moth caterpillars are not hairy and most have a characteristic horn at the rear end. They tend to be larger than the average caterpillar, growing up to 10cm in length, depending on the species. The garden hawk-moths are generally caterpillars from June or July to September and several species are regularly encountered by gardeners – particularly the Elephant Hawk-moth but also the Eyed, Lime, Poplar and Privet Hawk-moths.

Many of these moths are named after their main caterpillar foodplants, which are often trees. Privet Hawk-moth feeds on Wild and Garden Privet, Ash, Lilac and Guelder-rose. Poplar Hawk-moth uses poplars, sallows and willows. Lime Hawk-moth chooses limes, elms, Downy and Silver Birch and Alder.

Eyed Hawk-moth caterpillars feed on wild and cultivated willows and sallows, also Apple and Crab Apple. They are named from the black and blue eyes on a pink background on the hindwings of the adults, which are flashed if provoked to deter predators. Finally, Elephant Hawk-moth caterpillars have an extendable snout that resembles an elephant's trunk. They feed on Rosebay Willowherb, Great Willowherb, other willowherbs and bedstraws and fuschias.

Privet hawk-moth caterpillarThese moths overwinter as pupae below ground, at varying depths, usually near the caterpillar foodplant. The Elephant Hawk-moth pupates in a cocoon on the ground among leaf litter or just below the surface whereas the Privet Hawk-moth pupa can be more than 30cm deep. As a result, in the autumn, remember to leave leaf litter around plants in the borders undisturbed as there could be moth pupae tucked away amongst debris or buried in the soil.

Hawk-moths are some of the most impressive, colourful and appealing moths. If you don’t have a moth trap to discover the inhabitants of your garden then why not go to a moth trapping event. Being able to handle an Elephant or Privet Hawk-moth will totally win you over and make you keen to enhance your planting to cater for them.

Happy Gardening! 

The Secret Gardener