Tall magenta spikes with six narrow petals rise above a reedbed in high summer, with opposite pairs of long leaves up the stem
Purple loosestrife, Lythrum salicaria.
Nature · Wildflowers & flowers
Purple loosestrife
Native · flowers Jun–Aug · fens, reedbeds and riverbanks
Lythrum salicaria — Lythraceae
A tall, magenta-spiked plant of fen, marsh, reedbed and riverbank, easy to see from a boat in summer. It is a rich source of nectar for long-tongued insects. Introduced to North America in the 1800s, it has since become a serious invasive weed there.
How to spot them
- ▸Tall spikes, up to 1.5 m, of bright magenta-purple flowers with six narrow petals, packed in whorls up the stem
- ▸Long green leaves in opposite pairs, sometimes in threes, up the square stem
- ▸Grows in wetlands — reedbeds, fens, marshes and riverbanks — throughout the UK, less common in Scotland
- ▸Look-alike: rosebay willowherb has four petals, alternate leaves and grows on dry, disturbed ground
- ▸Look-alike: yellow loosestrife is not a relative — it is in the primrose family, with yellow flowers
How to know it
Its long-tongued visitors include brimstone butterflies, red-tailed bumblebees and elephant hawk-moths
Purple loosestrife, per the Wildlife Trusts.
Taken to North America in the 1800s, this wetland plant now forms impenetrable stands that shade out natives
Purple loosestrife, as described by the Wildlife Trusts.
Its Latin species name refers to willow-like leaves, though it is no relation of any willow
salicaria — willow-like — purple loosestrife.
Wildflower of the reedbed with three different forms of flower, differing in the length of their stamens and style
Purple loosestrife is tristylous.
Not related to the yellow-flowered plants of the same common name, it belongs to the family Lythraceae
Purple loosestrife.
Quick-fire facts
- •Family Lythraceae, the loosestrife family — purple loosestrife is not related to yellow loosestrife, which is in Primulaceae
- •Wildlife Trusts: flowers June to August, up to 1.5 m tall, common but less so in Scotland
- •The Wildlife Trusts list brimstone butterflies, red-tailed bumblebees and elephant hawk-moths among the long-tongued visitors
- •Taken to North America in the 1800s, where the Wildlife Trusts describe it as an invasive weed forming impenetrable stands
- •Plants have three flower forms (tristyly), so an insect carrying pollen between forms fertilises them best
- •Lythrum comes from the Greek for 'gore', for the flower colour; salicaria means willow-like, for the leaves
- •The word 'loosestrife' is a translation of the Greek Lysimachia, said to honour King Lysimachus, who was said to have calmed a maddened ox with it
- •Native
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Sources
- The Wildlife Trusts — Purple loosestrife