Moles
Scalopus aquaticus & Scapanus spp.
Insect-eaters, not plant-eaters: the damage is heaved soil and severed roots, never a nibbled crop. The animal you blame for the eaten bulbs is almost always a vole.
How to know it
Rarely seen: a cylindrical gray animal about 15 cm long with pink shovel-like forefeet, no visible eyes or ears, and a pointed snout. Read the workings instead. A mole throws up conical heaps of loose soil with no hole in the side, and runs raised surface ridges; a vole leaves open holes the width of a thumb and clean-cut runways in the grass.
What you'll see
- Conical molehills of fine crumbly soil pushed up in a line across the lawn.
- Raised, spongy ridges just under the turf that give when you stand on them.
- Seedlings and small plants left wilted and loose because the run went straight under their roots.
- Damage that appears overnight after rain, when the worms come up and the mole follows.
- No gnawing anywhere — bulbs and roots are untouched, which is what rules out a vole.
Where it comes from
Solitary and territorial, active all year in a permanent tunnel system that one animal may hold for years — a lawn covered in hills is usually the work of a single mole, not an invasion. Breeding is in early spring and the young disperse in early summer, which is when a new garden acquires one.
Moist, worm-rich soil is the whole story: a well-mulched, well-watered lawn or border is a larder. Activity peaks in spring and autumn and after rain, and drops away in drought and hard frost, when the animal simply works deeper.
Dealing with it
- Decide first whether you actually mind — a mole aerates soil, eats leatherjackets and grubs, and takes nothing you grow.
- Rake the hills flat and use the soil, which is beautifully fine and weed-free potting loam.
- Firm the surface ridges back down with your foot and water in any plant that has been undermined.
- Where a lawn must stay flat, a scissor or harpoon trap set properly in an active deep run is the only method with good evidence behind it.
- Ignore the sonic spikes, mothballs and windmills; every trial finds they do nothing.
Keeping it out
- Line a raised bed or a bulb bed with wire mesh underneath where the digging is intolerable.
- Accept that reducing worms is the only real deterrent, and that a garden with no worms is a worse garden.
- Fence the vegetable plot with mesh sunk 30 cm and turned out at the bottom if a run is repeatedly cutting seedlings.
- Keep newly planted stock firmed and watered so a passing run does not dry the roots out.
- Look for gnawing before you blame the mole; the vole using its tunnels is usually the animal eating your plants.
What it goes for
Nothing is eaten. Lawns, seedbeds and newly planted stock suffer from the tunnelling alone.
See also
The Cottage Garden Companion — the gardener's bestiary at cottagegardencompanion.com