Tony Dickerson answers your questions
Q Are there any plants slugs won’t eat? Jo Butler, by email
AThe RHS lists about 50 herbaceous plants which are less likely to be eaten by slugs. If you Google ‘Slugs/RHS gardening’ you’ll get the link. Plants include a good selection of ornamentals such as agapanthus, Japanese anemones, Michaelmas daisies, foxgloves, euphorbias, geraniums, phlox, potentillas, rudbeckias, thalictrums and verbascums. These, however, are only a fraction of the thousands of garden plants we grow, most of which are slug food.
There are around 40 species of slugs in the UK and they’re active throughout the year, but only some cause damage to plants. Grey field slugs and keeled slugs that live in the soil cause most damage. Species of really large slugs tend to feed on decaying plant matter or other slugs, which makes them beneficial from the gardener’s point of view.
You can’t eradicate slugs permanently from gardens but there are a host of measures that help keep their numbers manageable. Regular cultivation and keeping the garden tidy will help reduce hiding places but if you want a wildlifefriendly garden you may have to forego an overly tidy plot.
Biological control, in the form of nematodes watered on moist soil about six times from spring to autumn, is effective but is prohibitively expensive for most gardeners. However, a strategic single application in mid-spring may help to reduce overwintering populations.
Other non-chemical approaches include scooped out orange or grapefruit skins laid cut side down or jars filled with lager or beer sunk into the soil near vulnerable plants. Check and empty regularly every morning. Hand picking on mild, wet nights with a torch is also effective. Copper tapes around containers also appear to work, although I don’t find the various barrier materials economic or particularly effective.
Metaldahyde-based slug pellets can be detrimental to other wildlife. Those based on ferric phosphate are approved for use by organic growers. Applied as directed, they give a good level of control. There’s no benefit in applying excessive amounts which simply spoil. Always apply as instructed. Once slugs disappear repeat the application.