Leaf
Catherine Bouvard, Tela Botanica · CC BY-SA 2.0
Redshank
Persicaria maculosa Gray
Also known as: Lady's thumb, Spotted knotweed
Family: Polygonaceae
20 to 80 cm
Crops, ditch edges, damp ground
Flowering: June – October
Full sun
Part shade
Hardy to about -20°C
❓ How do you recognise this plant?
A dark crescent-shaped blotch often marks the centre of each leaf. Common bistort has a single, longer cylindrical pink spike at the top of a bare stem, with no blotch on the leaves, whereas redshank has shorter, denser spikes, with often a dark V-shaped blotch on the leaves.
🍃 Leaves
Lanceolate, often marked with a dark blotch at the centre
🌸 Flowers
Small, bright pink, in dense, compact spikes
🍎 Fruits
Small brown lens-shaped achene
🪵 Bark
Knotty herbaceous stem, membranous sheath at each node
🗺️ Distribution
Europe, temperate Asia; common in France in crops and wet areas
🐝 Value for pollinators
Pink spikes rich in nectar, visited by bees and hoverflies in late summer
✂️ Horticultural uses
Regarded as a crop weed, with no ornamental use
⚠️ Possible toxicity
No known toxicity; sap slightly irritant to some sensitive people
⚠️ Look-alike species
Redshank
Persicaria maculosa
Common bistort
Bistorta officinalis
Common bistort has a single, longer cylindrical pink spike at the top of a bare stem, with no blotch on the leaves, whereas redshank has shorter, denser spikes, with often a dark V-shaped blotch on the leaves.
🌿 Other Polygonaceae to discover
ℹ️ Educational profile — do not use it to judge whether a plant is edible or safe.
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