Gardening With Insects

On Wednesday I was honoured to have the opportunity to speak to the North Waltham Gardening Club on the subject of insects in gardens. I couldn’t have been more delighted with the warm welcome I received and the attentive, engaged nature of the audience – and I’m not just saying that to be nice! North Waltham is a small village near Basingstoke in Hampshire, and a very fine one at that, though I may be biased due to having lived there for a couple of years (my parents still do). Despite its small size it has, as so often seems to be the case, a better community feel than we have in the Reading suburbs and evidently a good number of keen gardeners.

I put the talk together by asking two questions – what do gardeners want to know about insects, and what do they need to know (but might not have thought to ask)? It seemed that the best place to start would be to consider what an insect is, within the wider context of invertebrates. I focussed on terrestrial invertebrates, i.e. all non water-dwelling animals that don’t have backbones. That is to say, most of them. That part of my talk was based on an ID resource I’ve been developing as part of the Invertebrate Survey MSc  module at Reading, which I hope to finalise and share soon. In the meantime, the most important message is that to get started with invertebrate identification one needs only to be able to count up to eight! All the animals you encounter will fall into one of four categories, possessing zero, six, eight or ‘more than eight’ legs.

A speckled bush-cricket in our Ruscombe front garden. Six legs and not a springtail (or one of two more obscure soil-dwelling groups) = insect.
A speckled bush-cricket in our Ruscombe front garden. Six legs and not a springtail (or one of two more obscure soil-dwelling groups) = insect.

I went on to speak briefly about insect conservation. Changes in insect populations – driven by an enormous range of factors but including widespread landscape change in the latter half of the twentieth century – mirror the declines seen in groups such as birds. For example, 60% of invertebrate species assessed for the State of Nature report were found to be in decline, around 35% of these strongly so. However, only 4% of invertebrate species in the UK are well monitored enough to have been included in the report. In this context gardens potentially have much to offer as insect habitat, comprising as they do a diverse mosaic of patches which could serve as oases of shelter and nectar-bearing plants in the wider countryside and green corridors through towns and cities. Click on the pictures below for full captions and the full story.

The main part of my talk was a rogues gallery of common garden insects. I considered pests such as aphids, beneficial insects – including many that eat aphids! – and a host of others which offer no particularly useful service beside looking lovely but do little harm either.

Finally, I tied these threads together with a few thoughts on how best to garden for and with insects. Anybody who had seen my previous attempts at growing anything would find the idea of me giving advice to a room full of gardeners laughable, but I hope the audience found what I said useful. My main points were:

  •  Diversity is good, whether in the flower border or in lawns. Have a go at establishing a wildflower meadow!
  • Try to stick with natural pest control, for persistent problems at least avoid the more indiscriminate pesticides. Especially steer clear of those sprays which have a neonicotinoid as the active ingredient (check labels).
  • Avoid ‘over-tidying’. Lay off the pruning shears until mid Autumn at the earliest. What to us are weeds are life-giving food plants for many insects.
  • Provide over-wintering habitat for insects, such as evergreen shrubs or log piles.

I also briefly showed a long list of plants known to be good for encouraging bees in the garden, which I lifted from Dave Goulson’s website.

Now that this talk has been tested, and I’ve had a chance to figure out which bits work best and which bits might want switching around, I’d love the opportunity to take it on the road again. Invitations from other gardening clubs or similar interested groups will be gratefully received!

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