Purple loosestrife
Lythrum salicaria
Botanical family: Lythraceae
Lythrum salicaria raises its long purple spikes at the water's edge in late summer. Native and generous in France, it has nonetheless become one of the most feared invaders of North American wetlands.
Full sun
Bank, moist to flooded soil
Feet in the water or waterlogged soil
Very hardy
Overwinters in your zone
Role in permaculture
A great nectar plant of late summer: its spikes feed bees, bumblebees, and butterflies at a season when flowers grow scarce, and its root system stabilises pond and ditch banks. A key piece for the life of a water point.
Companions
No companion planting is documented for this plant: no recommended neighbour, no neighbour to avoid.
Seasons & availability
Purple flower spikes gathered in summer, from July to September, by the water; dried for the rest of the year.
Available: January, February, March, April, May, June, July, August, September, October, November, December.
Guidance for the oceanic / temperate climate; it may vary with your region, altitude, exposure and growing method.
Sources
- Plants For A Future, « Lythrum salicaria » (pfaf.org/user/Plant.aspx?LatinName=Lythrum+salicaria)
- Tela Botanica, « Lythrum salicaria L. » (tela-botanica.org/bdtfx-nn-40631-description)
- Missouri Botanical Garden, « Lythrum salicaria » (plantfinder.mobot.org/PlantFinderDetails.aspx?taxonid=282500)
Nutritional & medicinal properties
For educational purposes. Not a substitute for medical advice. Effects depend on the form, the dose and personal context.
Precautions & contraindications
Astringent (tannins): occasional use; diarrhoea that persists calls for medical advice. Do not confuse with the neighbouring willowherbs.
Species & varieties
The best-known species and varieties in France.
Common varieties
Keep in mind
Precious and native in our wetlands, purple loosestrife is conversely a major invasive alien plant outside its native range (banned from sale in several North American states). In France: to be installed in a garden pond or basin, never near a sensitive natural watercourse. Outside mainland France, check its status before planting it.
A note on rigour: many companion pairings are gardening folklore; this note sums up what the sources say, where there are any.
Before you forage
This plant is often gathered from the wild. Only pick what is abundant, never a protected species, and never uproot a whole plant (roots) without the landowner's permission. Rules vary by country and region, check locally.
Key takeaways
- • Prefers full sun exposure.
- • Ideal soil: bank, moist to flooded soil.