Eupatorium maculatum

Something of a lovable monster of a perennial that’s often planted at the back of grand herbaceous borders, this is a useful plant for screening ugly walls or fences in summer, and if you leave the big domes of flowers intact after the bees have finished (butterflies love them, too), they’ll add winter structure to the garden. It grows to 2m tall and wide and does best in sun or part shade in soil that isn’t quick to dry out.