There are two symptoms of moles: mole hills - piles of excavated soil on lawns and around the garden - and underground tunnels, found when digging the soil or making a new planting hole.

Mole hills - piles of fresh, excavated soil - don't fully convey the extent of one mole's underground tunnel system, which can cover a surprisingly large area. If a young plant isn't developing, it could be due to tunnelling beneath it. Seedlings can also suffer badly when their roots are disturbed, or they're left dangling in an empty space.