Willow weed (Persicaria maculosa)
Prefers moist well-aerated ground. Annual.
Identification
Its leaves are similar in shape to those of the willow tree, with a distinctive brown marking in their centre. It has small pinkish flowers and stems with a reddish tinge. Water pepper is often mistaken for willow weed.
Characteristics
Germinates in the spring and dies in the autumn. Can grow across the ground or upright when amongst other plants.