Lythrum salicaria (purple loosestrife) — Clump forming

Overview

Lythrum salicaria is a clump forming perennial herbaceous in the genus Lythrum, part of the Lythraceae family, with deciduous foliage. It typically grows around 1.0 m tall. Lythrum salicaria grows best in full sun, and tolerates most soils and any pH. Its UK hardiness is rated H7. Suggested uses include cottage and informal garden, wildlife gardens, wildflower meadow and flower borders and beds. It is native to Old World.

About the genus

Lythrum is a genus of 38 species of flowering plants native to the temperate world. Commonly known as loosestrife, they are among 32 genera of the family Lythraceae.

Wikipedia contributors, "Lythrum", CC BY-SA 4.0 — Lythrum

In the garden

Lythrum salicaria is a perennial herbaceous member of the Lythraceae, native to the Old World, that produces recognisable purple flower spikes in mid to late summer. Plants normally grow to about 1.0 m and offer a long flowering window from July to September. The species has a broad native distribution across temperate regions of the Old World. For cultivation give the plant a sunny position and soil that remains moist; it adapts to sandy, loamy or clay soils. It will tolerate waterlogged conditions as well as moist but well-drained ground. In British terms it is H7, fully hardy, and its USDA range (zones 3–10) reflects a wide tolerance of climates across seasonal extremes. In the garden it suits pond margins, damp borders and naturalistic or rougher planting schemes where soil stays reliably damp. Allow for its upright habit and flowering season when planning adjacent planting so its purple blooms from July to September are visible at eye level. Regular observation of soil wetness in periods of drought is the main cultural consideration for keeping flowering consistent into early autumn.

Growing conditions

Best soil and position for Lythrum

Sunlight: Full sun
Soil type: Sandy, Loamy, Clay
Soil pH: Acid, Alkaline, Neutral
Soil moisture: Moist but well-drained, Wet
Aspect: South-facing, East-facing, West-facing
Exposure: Exposed, Sheltered
UK hardiness: H7

Plant details

Lythrum salicaria size, habit and characteristics

Plant type: Perennial herbaceous
Habit: Clump forming
Foliage: Deciduous
Height: 1.0 m
Suggested uses: Cottage and informal garden, Wildlife gardens, Wildflower meadow, Flower borders and beds
Native to: Old World

Care notes

Pruning and caring for Lythrum salicaria

Propagation: Division in spring
Pest resistance: Slugs, Snails
Disease resistance: Generally disease-free

Frequently asked questions

Where is the best place to plant Lythrum salicaria?

Lythrum salicaria prefers full sun. It suits exposed and sheltered positions.

What soil does Lythrum salicaria need?

Lythrum salicaria is adaptable and grows happily in most soil types, including sandy, loamy and clay. It is happy in soil of any pH. Aim for soil that stays moist but well-drained to wet.

How big does Lythrum salicaria grow?

Lythrum salicaria reaches a height of 1.0 m.

Is Lythrum salicaria hardy in the UK?

Lythrum salicaria has an RHS hardiness rating of H7, meaning it is fully hardy throughout the UK, tolerating temperatures below -20°C.