Did earthworms kill my primroses this year?

Jennie Wootton, by email

Stefan says: The earthworms won’t be the cause of the death of your plants. In a highly organic soil, with a very high worm population, I suppose they might move the soil so much that the roots were disturbed, but it’s far more likely the plants were killed by a soil pest, probably vine weevils, and that the earthworms have simply been attracted by the rotten roots.

Apart from some species of earthworms being the bane of greenkeepers’ lives by producing soil casts, no species of earthworm causes any harm and most are extraordinary beneficial, in fact crucial, to gardens and the wider environment. They aerate the soil, they break down organic matter and, of course, they provide food for many birds and other creatures.