Root and Branch

The rule of sixty

Save your shrubs with a slug pub, says Hephzibah Anderson

This article is taken from the May 2021 issue of The Critic. To get the full magazine why not subscribe? Right now we’re offering five issue for just £10.

Anyone tempted to toast the latest roadmap milestone with an al fresco pint at their local will have had to either obey the rule of six or take care not to socialise with members of more than one other household. No such restrictions apply down at the allotment, where it is a case of the more, the merrier. There’s just one entry requirement: membership of the phylum Mollusca.

Drawn to its sugary, yeasty promise, slugs tumble in to meet a sozzled end

The slug pub, as I’ve taken to calling it, consists of a network of submerged jars filled almost to the brim with beer, the cheaper the better. Drawn to its sugary, yeasty promise, slugs tumble in to meet a sozzled end. It’s a key weapon in the annual battle against marauding molluscs that have already claimed tender broad bean plants and
overwintered opium poppies (they’re a badass crew, this lot).

Last year, a notably mild winter followed by a torrential spring turned our allotment into a slug stronghold. Nothing was safe. A carpet of white violets was deflowered before it had the chance to bloom. Fiery radish shoots were decapitated the moment they poked their heads above ground. Carefully nurtured courgette plants became silvered stumps overnight.

This year, we have on our side a frosty winter and a dry start to spring, but don’t be fooled: we’re up against a horror-movie-esque enemy. These nudist snails have more “teeth” than a great white shark — 27,000 on average. They’re actually denticles, edging a conveyor-belt-like radula with which slugs can rasp their way through 40
times their bodyweight daily. Sometimes, you can even hear them at it. Almost nothing is off-menu, however unsavoury, meaning they’re also vectors for parasites including lungworm, a particular threat to dogs.

They are, of course, anything but sluggish. They can stretch 20 times their length to squeeze through the narrowest of gaps, and their mucus puts off predators with its bitter gumminess, leaving in their wake the tell-tale trails that also serve as slug highways, signposting the way to particularly delectable banquets.

It’s said that at any one time, approximately 95 per cent of your garden’s slug population will be lying in wait below ground. Add to this their ability to self-reproduce — a single slug could conceivably acquire 90,000 “grandchildren” — and you can see why they’ve so taxed human ingenuity.

Over 200 years ago, one John Wilmot, a fellow of what would later become the RHS, could be found bewailing the ravages of these “nocturnal depredators”. His answer was a kind of liquid lime. I haven’t yet tried that but here are some of the tricks I have used: wool pellets, coffee grounds, crushed eggshells, seaweed gathered at low tide, grapefruit halves, wood traps, hand-picking (a fellow allotmenteer lost count at 120 one evening), hedgehog-enticing.

It’s worth noting that even were you able to eliminate them entirely, the very absence of slugs would leave you vulnerable

To be trialled this season are human hair, caffeine solutions (aka a double espresso or two), the comfrey method
(using inviting piles of leaves as traps, allowing for mass deportations), and trays of bran (slugs will apparently gorge on it, causing death by desiccation — unless they literally pop first). Had I any raised beds, I’d try stapling wet-and-dry sandpaper to the rims, and I may yet be driven to duck-napping (they love slugs). There are also nematodes, mail-order micro-organisms that kill off slugs by infecting them with bacteria. So far, though, only beer has had any real impact, and take it from me, the resulting brew is not for those with a sensitive nose.

It’s worth noting that even were you able to eliminate them entirely, the very absence of slugs would leave you vulnerable, since it would also cause any resident predators to wander off. For all their malicious-seeming destruction, slugs remain an important part of any garden ecosystem, and not all are your enemy, either.

Take, for instance, the leopard slug. It prefers dead and rotting plants, fertilising your soil by helping to recycle them, and a penchant for cannibalism means that those slugs that are likely todamage your living plants had  better watch out. All the same, it seems tauntingly ironic that the collective noun for these guzzling gastropods should be a cornucopia.

Any reader despairing of my organic predilections and wondering why the heck I don’t just sprinkle slug pellets should note that, from the end of March 2022, the most effective pesticide-based kind are to be banned in the UK, due to the risk they pose to birds and mammals. That same ban has spurred on a government-funded invention called the SlugBot. Due to enter field trials this summer, it uses AI to detect slugs, and then precision- sprays them with eco-friendly bio-molluscicides. We can but dream.

Meanwhile, never let it be said that wildlife-friendly gardening is for the lily-livered; on the contrary, it can sometimes feel like a blood sport, it’s just that the blood runs aphid green. Now, if you’ll excuse me, I’ve a date down at the slug pub.

Enjoying The Critic online? It's even better in print

Try five issues of Britain’s newest magazine for £10

Critic magazine cover