Admittedly, autumn might seem like an odd time of year to be talking about Hostas, plants famed for their luxuriant spring and summer foliage… but stay with me here. As I look outside my own kitchen window, I can see the Shady Table hostas yellowing and some are now translucent. They’re all winding down for winter, so why talk about them now? Well, this is the time of year when us gardeners can kickstart our anti-mollusc masterplan and get one step ahead of those villainous slugs and snails.
It begins with a pre-winter tidy
Like all truly herbaceous plants, hosta leaves die in autumn. If you’re new to hostas and you’re worried about yellow leaves in September, then stop worrying. It’s perfectly natural and just their seasonal cycle. However, unlike most other plants, it’s essential to remove those leaves, before they collapse into a semi-translucent mush.
Cut them right down to the ground! Don’t leave even so much as a wisp of leaf. You can twist and pull leaves out, like you would rhubarb, but I find this often leaves nasty ragged ends. I prefer to cut and compost. By doing this simple act, you’ll be one step ahead of the hosta’s mortal enemy… those marauding molluscs!
Removing the leaves, takes away anything that will attract them, any potential food and crucially any cover for those slimy soil dwellers. Over the winter, without cover of fallen leaves, any slug or snail eggs are subjected to both hard frosts and hungry birds, eager to pick over the surface, scouring for those pearly spheres. Don’t complain that the birds are making a mess. By the time spring arrives, you’ll already have fewer slugs and snails to contend with.
Spring assessment
Having removed all the leaves earlier in autumn, we now put the next part of the plan into action. Every year, in late winter or early spring, you need to assess and redress all your container grown hostas. This is the process I follow when I see those first hard shoots nosing through the compost:
-
Lift the pot, or roll it on its side, check there are no slugs or snails hiding in the drainage holes! They are cunning little blighters and will happily overwinter in the gap between the base of the pot and the crock or drainage layer inside. But not before laying eggs in the compost above… Clever!
-
Next, run a hand fork or daisy grubber around the inside of the pot rim to dislodge any (tiny) slugs or snails hiding under the compost/soil surface.
-
Remove any weeds, moss and detritus lying on the surface.
-
Take a hand fork (or gloved hand) and gently scratch over the compost surface, taking care not to damage any shoots nosing through. Clear away all the old surface compost you’ve just raked up.
-
With a clean surface, apply a single dose of Fish-Blood-Bonemeal, followed by a fresh layer of good quality bark-based compost. Water this in to settle it down.
It doesn't seem like much, but we have accomplished two important things here. Firstly, we’ve removed any existing slugs or snails from the pot (a combination of frosts, birds, and beetles will have reduced or removed any eggs laid beforehand). Secondly, we’ve given the hosta a dose of fertiliser and fresh compost for more vigorous, healthy foliage that does not lag or linger.
Divide and thrive
Spring is also the perfect time for a stocktake! Were any of your hostas particularly or inexplicably weak the previous season? Are there any hostas that look crammed in, growing edge to edge in their pot? (Label those pots now so you remember!)
It might sound obvious, but pots do have a finite capacity for roots. Essentially, pot-bound plants can't find enough food and/or water to sustain the growth above. No matter how much you water or feed them, the plants are lacklustre and weak. In extreme cases, there's actually more root than compost and hostas have particularly thick and fleshy roots.
Most of my larger hostas, like Blue Angel, Halcyon and Bressingham Blue, are in pots measuring 40-50cm across at a minimum. In late winter 2022, these hostas were removed from their pots, unceremoniously plonked on the paving, then brutally chopped up with a spade. It was simple and effective.
Don't worry. These are TOUGH plants!
You can use a sharp spade, a hori hori, or an old hand saw. Whatever you use, cut vertically through the rootball. I divided mine into quarters, replanting two quarters together in pots, all surrounded by lovely, fresh, nutritious compost. I made my own mix with a blend of Sylvagrow multi-purpose compost with John Innes, garden compost and Sylvagrow Composted Bark. I try and mimic the natural woodland environment of hostas.
The subsequent divisions have grown so well, they need dividing yet again. It’s a little work, but on the plus side, it means free plants and what self-respecting gardener doesn't like free plants?!
"And a quick word on pots... many ceramics have a bowl shape that pinches-in, a little way below the rim. This design 'flaw' can be really inconvenient when it comes to removing a pot-bound plant and might even mean you have to smash the pot to get the plant out. I swear it's a conspiracy to make us buy new pots! Bearing that in mind, look for straight-sided pots or bowls without that annoying pinch point."
Strength through the season
After assessing, redressing (and dividing if required), the only job you need to do thereafter is watering, especially after the leaves begin to unfurl. Give your hostas a real drenching, once per week, rain or shine.
When those large luscious leaves have fully unfurled, very little rain will reach the compost surface of pot-grown plants to replenish thirsty roots. You must water regularly! Keep an eye on the leaves. If they begin to droop, it’s a sure sign they need more water.
FYI: Hostas are well known as moisture loving plants, but that doesn’t mean they like to sit in stagnant waterlogged compost, so do make sure your pots can drain and any compost mix you use can drain too.
If at all possible, watering should be completed in the mornings. You’ll want all the surfaces to be as dry as possible by nightfall, making it harder (and far more energy draining) for those malevolent molluscs to go rampaging through your plants. Yes, there will always be plenty of rain for them to move about, but why make it easier for them?
With that initial feed, and regular water, hostas will grow fast. When plants are stressed, whether it’s lack of water or nutrients, the first thing to suffer are the leaves. Stressed leaves are vulnerable! Molluscs detect these weak leaves and home in like laser-guided slimy torpedoes. If you have yellowing leaves, just remove them. They’re no longer photosynthesising, just attracting and harbouring pests.
Preserving that fine foliage
From June, hostas throw up tall flower spikes or 'scapes'. After pollination, the plant’s natural reproductive cycle is complete and the plant naturally begins to wind down. Essentially, its job is done for the year - metaphorically claps its hands and says “Goodnight!” The leaves begin to lose colour, shape, and that particular lushness we find so alluring.
So, be brave and prune out the flower stems. Personally, I’m not a fan of them aesthetically and although the bees seem to like them, the vast majority of my garden has been designed for pollinators anyway - there are plenty of other options for those little fuzzy-butts.
Removing the flowers before they open helps maintain the hosta’s vigour and the leaves stay looking better for longer. Hostas will continue to throw up new stems, but keep pruning them out. At this time, should you wish to, you can give your hostas a regular seaweed feed, but I really haven't found this to be necessary. Over-feeding can lead to foliage that grows too lush and soft.
Encouraging garden friends
In my garden, there are lots of birds and I go out of my way to encourage more. Blackbirds, Song Thrush, and Starlings are all voracious predators of slugs and snails. I often hear a sharp tapping when I'm in the garden. When I locate the source, it's often a blackbird or song thrush smashing the life (literally) out of a snail so I leave large stones or bricks in the borders as anvils. Hedgehogs, ducks, chickens, frogs, toads, slow worms, ground beetles are all particularly fond of a meaty mollusc!
To encourage the garden birds, I feed them on makeshift bird tables (near the hostas) as they're happiest feeding on the ground, or at least a flat surface, as opposed to hanging on a bird feeder. But, importantly, I only feed in the morning and they spend the rest of the day scouring the garden borders, beds, and pots for food, doing a marvellous job of controlling would-be pests in the process.
We also have lots of frogs but no actual pond (yet). I do have a large area of uncultivated wild and weedy habitat - The Embankment - and it is here I find the most frogs. A close second, in frog numbers, is the Flower Garden, even though it's a dry and sunny spot. But the extremely dense covering of plants provides both shade and moisture at ground level, where they happily shelter during the day.
Gardening organically
Organic gardening methods create a natural balance between predator and pest. All my gardens are 'no dig' and there are no chemicals whatsoever, so the soil is healthy and alive. There are also lots of twiggy piles, log piles, and other places of cover. The result is a very healthy population of slug and snail eating beetles including:
-
Lesser Stag Beetle (Dorcus parallelipipedus)
-
Ground Beetle (Carabids)
-
Devil's Coach-Horse Beetle (Ocypus olens
-
Black snail beetle (Phosphuga atrata)
Is your garden suited to hostas?
Hostas are such beautiful foliage plants with those luxurient leaves. They make such a rich, verdant display here on the Shady Table, my purpose-built stage for the hostas. Without doubt, the most frequently asked (Instagram) question I receive is:
"How do you keep your hostas looking so good?”
Sadly, there is no one secret or 'fix all' magic bullet (despite what you might read) because all our gardens have their own microenvironment and ecosystem. Saying that, I have now shared with you every aspect of how I grow hostas, which certainly seems to work here. But where are we talking about?
My garden is in South Oxfordshire, England. It's a maritime USDA zone 8b equivalent. My hostas are all in galvanised or ceramic pots and planters, placed on a table, or on the ground, tucked under a north-facing gable-end... on a stone terrace.
Why am I telling you this? Well, it's a particularly dry area of the garden. The north-facing site is sheltered from the predominantly westerly rain. The terrace is open and relatively tidy with few hiding places for the slugs and snails, save the cracks in paving. This all helps!
Some gardens are inherently massive mollusc habitats, whether it’s because there is so much cover, or lots of hard landscaping providing invulnerable hidy-holes to avoid predation by birds. Some urban gardens are just shady and damp all the time, perfect for the rapacious mollusc.
So, as with anything in gardening, pick your battles. Try the tips above, but if your hostas are still shredded, you may just have to accept that, regrettably, yours is not a garden for hostas. There comes a point where fighting a lost cause is just miserable and unsustainable. I certainly couldn’t plant any hostas in my Cottage Garden borders as they will be massacred.
Worth mentioning...
Perhaps an understated factor in avoiding pest damage is cultivar selection. It’s fair to say that I am very careful with which cultivars I buy. I tend to grow the glaucous cultivars with thicker, less palatable leaves. Personally, I think this is a critical attribute. Halcyon, Blue Angel, Bressingham Blue, Mouse Ears all lie within this category.
Slug Pellets and Pesticides
I never have nor will I ever use slug pellets. Pesticides are indiscriminate poisons and should not be on general sale. That’s my opinion anyway and I’m sticking to it. I won't use the ‘organic’ pellets either as the binding agent in many of these products is a problem in itself.
Of the 40 species of slug in the UK, less than 20% cause any significant harm to our precious ornamentals and crops. The vast majority feed on decomposing matter and some, like the Leopard Slug (Limax maximus), actually predate on other slugs, so you’ll want to keep these around!
If you apply pellets indiscriminately, you risk harming the beneficial populations of mollusc that you actually need in your compost heap. Those that clear away the natural detritus of your garden, not to mention the world at large. The knock-on effect continues as these chemicals potentially harm the natural predators of molluscs such as birds, frogs, hedgehogs, etc.
Barriers and traps
As for barriers and obstacles, I have tried wool pellets, when my hostas were growing in the Cottage Garden borders. It was a stupendous failure. The slugs and snails made themselves at home under the moist warm wool, only to appear at night and literally shred the hostas!
I’ve never used copper tape. Nor 'protective mulches' like eggs shells, coffee, grit, or anything like that. The RHS ran a trial testing 'mulches' in combination with pellets and the mulches actually appear to increase the damage?!
You could try beer traps, but then again you’re actively attracting slugs to your garden, so maybe not a great move either. In my experience, nematodes have been effective in the Kitchen Garden, but they do need several applications through the growing season. They’re most effective on smaller slugs but have no effect on snails.
Please don’t misunderstand. I’m not saying ‘don’t bother trying any of these products’ as they may well work for you and, judging by the reviews and evangelical hype by some gardeners, there must be some successes! Just don’t bank on them. A more effective targeted solution is to strap on a head torch and gloves, grab a bucket and go out on a nocturnal hunt, disposing of any ‘slimers’ as you see fit. I put mine on the compost heap or throw them into the bridleway. Let’s not be cruel though!
Here, in my organic garden, the most assured method of keeping my hostas free from damage safely and humanely is careful cultivar selection, a winter tidy and spring redress, growing them healthy and strong all season, and creating a welcoming garden to predators that control the mollusc population naturally. Having watched my hostas flourish over the last few years, it’s safe to say this is a method that will endure.
Add comment
Comments