Why make an insect hotel from prunings?

Walk into any garden centre and you will find brightly coloured insect hotels, often made from plastic and shipped halfway around the world. They look tidy, but many are poorly designed: the tubes are too short, the holes are the wrong size, or the whole thing traps damp. You can do far better with a pair of secateurs and the prunings you were about to put on the compost heap. A home-made hotel costs nothing, shelters local solitary bees and other beneficial insects, and gives you a satisfying reason to leave some garden waste lying about. It is also a lovely project to do with children on a damp weekend.

What garden insects really need

Solitary bees are the main guests you are aiming for. Unlike honeybees, they do not live in colonies. Each female finds a hollow tube, lays a series of eggs inside, packs each one with pollen and nectar, and seals it with mud or leaves. The larvae overwinter inside and emerge the following spring. Other insects will use your hotel too: ladybirds, lacewings, earwigs and beetles may shelter in twigs and leaf litter.

For solitary bees, the essentials are:

• Hollow stems with one closed end, so the bees have a back wall to work against.
• Tubes between 2mm and 10mm across, with a range of sizes to suit different species.
• Lengths of 10cm to 20cm — shorter tubes produce more males, longer ones are more useful.
• Dry, draught-free shelter that faces the morning sun.
• No pesticides, no plastic, no treated timber near the nesting tunnels.

Gathering the right hollow stems

You probably already have suitable stems in your garden. The best are old flower stalks that have dried naturally and have a hollow centre. Good candidates include:

• Bamboo canes that have split or gone brittle.
• Elder, teasel, bramble and buddleia stems.
• Sunflower, fennel, dill and tall grasses.
• Hydrangea and climbing rose stems, once they are dead and dry.

Cut them into lengths of 10cm to 20cm. Try to keep one end closed — the natural node or joint in the stem is perfect. If both ends are open, the bees will still use the tube, but they prefer a back wall. Use secateurs to trim any jagged edges, then rub the cut ends smooth with your thumb. This matters: rough edges can tear delicate wings.

Leave the stems somewhere dry for a few days before building. Damp stems grow mould, which kills bee larvae. If you are cutting fresh prunings in autumn, let them dry in a shed or greenhouse. Do not bake them in an oven or soak them in bleach; plain air-drying is best.

Building the bundle or frame

The simplest design is a tight bundle of stems tied together with garden twine. Gather 20 to 30 stems of mixed diameters. Hold them so all the closed ends are at one end of the bundle. Wrap twine around the bundle in two or three places, pulling it snug. Do not use wire, which can rust and cut into the stems, and avoid plastic string that will snap after a season.

If you want something more robust, make a small wooden frame from untreated offcuts. A box 20cm wide, 20cm tall and 15cm deep is ideal. Leave the front open and the back solid. Pack the stems in horizontally, closed ends facing the back. Fill any gaps with smaller twigs or rolled-up corrugated cardboard — though cardboard is best kept for other insects and not for bee tubes, as it goes soggy.

You can also use an old terracotta flowerpot. Fill it with stem bundles, then lay it on its side in a sheltered spot. Another option is to tie the bundle directly to a south-facing fence post. Whatever you choose, make sure the tubes are horizontal or tilted very slightly downwards at the open end. That keeps rain out while letting the bees in.

Where to site your insect hotel

Position matters more than fancy construction. Solitary bees need warmth to fly, so choose a spot that gets morning sun and is sheltered from strong wind and driving rain. A south-east or south-facing wall or fence is ideal. Mount the hotel between 1 metre and 2 metres above the ground — high enough to avoid damp and predators, low enough to be easy to watch.

Keep it away from bird feeders, which attract tits and other birds that will happily eat bee larvae. Do not hang it directly above a pond or a compost heap, as both create humid air. And please avoid moving it once bees have started nesting. They remember the location and will return to the same spot next year.

Add twigs, leaves and a little mess

A bee hotel is only part of the picture. Many garden insects need loose, damp places to hide. Pile up a few handfuls of twigs and dead leaves in a corner behind a shrub. This makes a perfect overwintering site for ladybirds, ground beetles and hedgehogs. Leave a patch of long grass uncut through winter. Let a few hollow stems stand in the border rather than cutting everything back in autumn.

Clean your stem bundle every two years, in early spring before the bees emerge. Gently pull out the old tubes, tap them to remove debris, and replace any that are cracked or mouldy. Fresh stems from your next pruning session will keep the hotel useful for years. With a little patience, you will see leafcutter bees carrying neat circles of green leaf, mason bees plugging tubes with mud, and a whole quiet world of garden wildlife making itself at home — all from a few prunings and a piece of string.