Purple Loosestrife
Lythrum salicaria
Print fact sheet (PDF)
Tall magenta spikes along the water's edge — and three different flower forms in one species.
A tall, handsome perennial of wet ground with square stems, narrow willow-like leaves and long dense spikes of star-shaped magenta-purple flowers. Purple loosestrife grows along riverbanks, ditches, fen and loch margins around Dumfries and is one of the most striking waterside plants of high summer.
Behaviour
The species has three distinct flower forms, differing in the relative lengths of styles and stamens, and successful pollination requires pollen to move between different forms — a system Darwin studied closely. It is a superb nectar source for bees and butterflies. Introduced to North America, it became a serious invasive there, which is a useful reminder that 'invasive' is about place, not species.
When to see it
Quick facts
- Family
- Loosestrifes (Lythraceae)
- Height
- 60–150 cm
- Status
- Native; common on wet ground
Photo by Ivar Leidus, CC BY-SA 3.0, via Wikimedia Commons