Buzzing buddleia

Exploring the (sometimes controversial) world of a garden favourite...

With insect numbers in rapid decline (it's estimated that 41% of our insect species are at risk of extinction in the UK), it's vital that we all do what we can to help our six-legged friends that make our world what it is. From pollinators to recyclers, we need our insects. Whether you've got a garden, a patio, a window box or a community space, you're able to do a little something; take a look at our Action for Insects page to find out more.

If you've got the space, you might have a patch of native wildflower meadow full of poppies or cornflowers, ox-eye daisies or bugle. Perhaps you allow ground ivy to scramble through your flower beds or ivy to clamber a wall. That's great! Our insects have learned to live with our native flora for millennia but in a world where they need all the help they can get, insects will also thank us for a range of non-native plants that offer food and shelter for more months of the year. If you've planted lavender or rosemary, lungwort or dahlias, you'll know how popular these can be with insects even though they're not native plants.

In my small patch of garden at home, I've got all of these plants mixed in with scabiouses, alliums, sedums, and more besides. Some are native, some aren't. One that isn't is a dwarf buddleia and the insects absolutely adore it. Buddleia is a controversial plant amongst conservationists. This pioneering garden escape is amazing at establishing itself in cracks between bricks, on railway embankments, brownfield sites and elsewhere. Apart from the obvious damage this can do to buildings and the like, it also smothers out native vegetation. Brownfield sites, in particular, can be surprisingly rich in native flora, and the wildlife it supports, so you can see why conservationists might get annoyed with this garden escape. It's estimated that buddleia costs the British economy just short of £1 billion a year for removal and repair so it's with an air of caution that I extol its virtue here and add a clear reminder to gardeners to ensure that dead flowerheads are removed before they're allowed to release their seed (more of which later).

Hummingbird hawk-moth hovering over and feeding from a pink buddleia flower by Wendy Carter — Hummingbird hawk-moth by Wendy Carter

Native to China, buddleias first arrived in the UK in the 1890s and, in modern times, have become a firm favourite for any gardeners seeking to attract butterflies to their garden. It's marketed as a butterfly bush and it certainly lives up to its name; regardless of which variety of buddleia you might have, it's a magnet for insects. On a sunny day or on a night-time safari, I can watch countless species of butterfly, bee, moth and other insects sitting amongst and feeding on the hundreds of tiny flowers that each flower head boasts. A top treat is the appearance of a hummingbird hawk-moth coming in for a sup.

Mullein moth caterpillar - mainly white body with yellow splodges and black spots by Wendy Carter — Mullein moth caterpillar by Wendy Carter

It's not just butterflies and bees that my buddleia attracts. Each year, along with my asters and echinops, it's home to speckled bush-crickets. I spot the first instar nymphs in May and then watch them grow into adults as summer progresses, often able to follow their wanderings by the lightly nibbled leaves they leave in their wake. I aim to provide nectar and pollen rich plants in my garden as well as ones that are suitable for caterpillars and other life-stages of insects to munch on. My buddleia is no exception. Because it's not native none of our wildlife relies solely on it but this doesn't stop moths and bugs laying their eggs on it. In the absence of their favoured mullein plant in my garden, for example, each year I have several mullein caterpillars chomping on the buddleia leaves.

Semi-dwarf buddleia in a garden for wildlife — *Buddleia davidii* buzz in a wildlife-friendly garden by Wendy Carter

I don't have a large garden so I'm not able to have a towering behemoth of a buddleia. Instead, I have a semi-dwarf cultivar in the ground and a couple in pots. The one in the ground grows to about six feet in height and I prune it to about three feet tall each March or April; each year I'm terrified of cutting it back too much but every summer I have a healthy-looking shrub that's dripping with life. I regularly deadhead the flowers until the final bloom, when I leave them for tiny insects to hide amongst over winter, ensuring that I remove them before the seeds ripen in the dry weather the following spring. I've yet to have any new buddleia bushes spring up from seed (my dwarf variety has bright pink flowers rather than the more typical purple flowers so I'd recognise it if it popped up somewhere else locally).

Buddleia isn't for everyone or every space and, if you have it in your garden, you have a responsibility to manage it so it doesn't escape. If you want an all-round wildlife plant for your garden and you have a suitable spot for one, I'd recommend a dwarf buddleia; mine is a Buddleja davidii buzz and can be grown in patio pots or in the ground (where it has much more vigorous growth).