‘It’s patronising to say that all slugs are friends – the RHS treats gardeners as nincompoops’

On a beautiful spring morning in the garden, with flowers stretching gleefully upwards, there are few more dispiriting sights for a gardener than slimy chemtrails of slugs leading to a host of the wretched creatures feasting in the serpentine border.

Yet apparently we should embrace our mollusc cousins, cease fulminating against them as they chomp through delphiniums, and make them our “friends”.

This is the aim of a new campaign by the RHS and the Wildlife Trusts, who have teamed up to urge us all to change our perceptions, encouraging us to appreciate slugs for the positive impact they can have.

“While a small number of slugs and snails can cause damage to certain plants, overall they bring many benefits to the garden and contribute to a balanced ecosystem,” says Helen Bostock, RHS senior wildlife specialist.

“We hope that by highlighting the crucial work that molluscs do in our gardens we can help give them a well-deserved reputation makeover.” But it may take more than a cheery campaign to make dedicated gardeners warm to the blighters.

“I have to say that I’ve never encountered a slug which engaged my enthusiasm,” says Victoria, a horticulturist with decades of experience and knowledge and a longstanding RHS member, who prefers to stay anonymous, possibly fearing the reaction of mollusc-lovers.

She frequently disposes of the pests given the chance.

“I don’t like their appearance, I don’t like the slime trails they leave. I don’t like the damage they can wreak. I don’t like them in the garden, or my cellar, or on my indoor carpet or the inside of my windows. They disgust me.”

She goes on: “I don’t like them on my bathroom floor; I don’t like them on my dinner plate…” an incident, she is quick to explain, that did not happen at home.

Victoria, who is known to spend ten hours a day, seven days a week working on her garden which opens each year as part of the National Garden Scheme, does admit being a bit discriminating. She does not kill them all on sight.

“It is true that there are many different types of slug and by no means all of them cause major damage to plants. I do find the markings on some of the large so-called leopard slugs quite intriguing – at a distance – and I am pleased that their diet mainly consists of detritus and, I understand, even some smaller slugs. This is something of a relief, because they are rather too big to squash.” 

Amongst the most damaging slugs are the small brown-grey garden slug, Arion hortensis. Like others, these slugs generally feed at night. 

Delphiniums, salads, seedlings, hostas all make tasty targets.

After a day of potting, one can find that by the morning, all the young, healthy, fresh seedlings have disappeared.

“One can often find them tucked away on the bottom of the pot, just inside the holes which are intended to allow the pots to drain,” says Victoria.

Slugs can reproduce both sexually and asexually; but that simply increases their capacity to survive and thrive, under many different circumstances. It means that wherever there is a damp, dark corner in the garden – in a pot, under a wood pile, between the leaves of my growing lettuce – there are the eggs, the young and the mature slugs.  

And it is, of course, impossible to kill all slugs, it’s more a matter of mitigation than engaging in an unwinnable war.

“Encourage predators - newts, frogs, toads, birds, hedgehogs,” says Victoria. “Not infrequently, I have been known to place small slugs on the ground, in inviting little piles of two or three, so that the robins, the blackbirds and even the young song thrushes that gather round my feet can consume them.”

One has to be careful with slug pellets. Metaldehyde pellets do work but are no longer available for good reason, they are dangerous to animals and children and polluting. 

Instead, use versions containing ferric phosphate are safer and suitable for organic gardeners.

Apply mollusc specific nematodes for biological control. Not that easy and should be applied before slugs multiply, but they do not work in cold temperatures. In cold wet springs, therefore, they are not very useful.

Hope for a cold winter and a not too wet spring. Possibly too hopeful these days.

Victoria isn’t convinced there are any particularly effective deterrents. “To be honest, most of the techniques for building temporary barriers around cherished plants – using eggshells, grit, wool pellets & any number of materials selected because slugs might not care to travel over them – do not work.”

And she whispers knowing someone who has been known to gather bags of snails and going for a long walk by a river with them where they can be humanely deposited.

But taking torchlit night walks to catch slugs of the move is worthwhile, catch them in the act.

Does Victoria use scissors to kill them?

“No – I squash them between two stones, or trowel and stone.”

And is she prepared to give the new campaign from the RHS, and Wildlife Trusts, a chance?

“The RHS now tends to treat all those who are interested in gardening as nincompoops or children,” she observes.

“It’s patronising to declare that all slugs have suddenly become our friends. Fair enough to point out that there are many different kinds of slug, and they do not all look the same and they are not all equally damaging. True, they are an inevitable, and sometimes beneficial, part of our ecosystem. But, talking about slugs threatening our ‘prized blooms’ is demeaning.

“Slugs are not just a little threat to our pride; there is no reason that we should learn to love them all. Slugs cause damage costing millions every year to crops – vegetable, arable and, of course, horticultural crops. In our gardens, slugs can frustrate our efforts, waste our time and our money. Many of them are, irrefutably, pests.”

Significant gardens, she says, have been a feature of the country for hundreds of years.

“Gardening is something which has taken up the time, the creative energy and the scientific research of people from all walks of life and yet it tends to be treated as a little bit of happy pottering. The value of the commercial horticultural industry alone runs into the billions.

“We do not all love slugs.”

And, sadly, they are not even the worst pests with which a gardener has to cope.

“Grey squirrels, scarlet lily beetles, vine weevils, honey fungus, various species of phytophthora … not necessarily worse, but just as bad. 

“No-one has told me I have to love them all … yet.”