They may conjure up images of ghostly goings-on around Halloween time, but bats should be welcomed into our gardens.

So says RHS senior horticultural adviser Helen Bostock anyway, who is urging people to make their gardens a haven for these bird-like mammals, as Wild About Gardens Week approaches. This year, the week is focusing on supporting bats.

Why should I welcome bats into my garden?

"Most of us are starting to grasp the idea that there are food chains, that gardens do have their own ecology, and if we start losing those higher up the food chain, including bats, that's not good news for the health of the garden.

"Moths are a big part of their diet, but they will also go for things that fly in dusk, like biting insects such as mosquitoes and midges. They will even go for beetles and insects on the wing. But they can pick off the odd insect if it's resting on a leaf.

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"Pest species of moth that will also likely end up as bat prey include tortrix moths, nibbler of many ornamental plants, especially conservatory favourites such as citrus; codling moth, familiar to any gardener who has bitten into a maggoty apple, and leek moth, the bane of leek growers."

According to the Bat Conservation Trust, the presence of bats, whose numbers have declined over the last 50 years, is an indication of a healthy, insect-rich environment.

What types of bat are there?

Pipistrelles are the most common British bats, weighing around five grams (less than a £1 coin). Yet a single pipistrelle can eat 3,000 tiny insects in just one night.

Other common types include our biggest bat, the noctule, which is still smaller than the palm of your hand, and the brown long-eared bat, which has exceptional hearing.

What plants to bats like?

Try to introduce a range of plants that will encourage moths and other food sources for bats into the garden, Bostock advises. Flowers with long, narrow petal tubes are favoured by moths; only their long tongues can reach deep down to the hidden nectar. Short-tongued insects, including many families of flies and some moths, can only reach nectar in flowers with short florets.

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"Adult moths are lured towards paler coloured flowers which show up at dusk such as hemp agrimony (Eupatorium cannabinum), night-scented flowers such as evening primrose (Oenothera biennis) and night-scented stock, long tubular flowers including common honeysuckle (Lonicera periclymenum) and Verbena bonariensis, open flowers such as cosmos and bishop's weed (Ammi majus), and aquatic plants such as aromatic water mint or purple loosestrife," she says.

Native plants attract far more species of insect than hybrids or exotics, so they should be used as much as possible.

 

We're only likely to see bats in the summer, about an hour before dusk, when they are foraging for food for their young.

So, how can gardeners help boost bat numbers?

The RHS advises:

1. Plant insect-friendly flowers such as Michaelmas daisies - these will attract insects such as moths and make a 'bat feast'

2. Stop mowing a patch of lawn to let the grass grow long, creating a habitat for insect larvae

3. Retain mature trees in a garden; those with hollows can make excellent bat roosts

4. Start a compost heap; lots of bat prey will live in it

5. Put up a bat box or build your own

6. If space allows, build a small pond or water feature - midges and aquatic larvae are the favourites of the pipistrelle bat

7. Reduce light pollution which disorientates bats - fit hoods to security lighting and only use low intensity garden lights

8. Avoid pesticides in the garden, especially insecticides that will reduce the prey of bats

9. In summer, keep cats indoors an hour before sunset when bats emerge from their roosts

Wild About Gardens Week 2016 runs from October 24-30. For details, visit the website.