Overview
Lythrum salicaria 'Robert' is a clump forming perennial in the genus Lythrum, part of the Lythraceae family, with deciduous foliage. It typically grows around 1.0 m tall. Lythrum salicaria 'Robert' grows best in full sun, and tolerates most soils and neutral pH. Its UK hardiness is rated H7. Suggested uses include borders, water gardens and wetland areas. It is native to Europe and Asia.
About
Lythrum salicaria 'Robert' is a perennial in the Lythraceae that forms upright stems to about 1.0 m bearing vertical spikes of purple flowers. It flowers from July to September. Plant in full sun on moist soils ranging from sandy to clay; it is fully hardy in the UK (H7).
Wikipedia contributors, CC BY-SA 4.0 — Lythrum salicaria
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 'Robert' is a herbaceous perennial from temperate parts of Europe and Asia, classified in the family Lythraceae. Plants reach roughly 1.0 m and carry vertical clusters of purple flowers through the summer and into early autumn, providing sustained colour from July to September. Place 'Robert' where it receives full sun and where the soil remains reliably moist; it tolerates sandy, loamy and clay substrates. Soil may be wet rather than drought-prone, so sites at pond edges, seepage lines or low-lying border ends suit it best. In British conditions the cultivar is rated H7, meaning it will survive normal outdoor winters; it is also hardy in USDA zones 3–10. Use this cultivar in damp borders, water gardens and wetland planting where upright summer colour is required. At about 1.0 m tall it works well as a mid-border vertical accent or at the margin of a pond. Because its flowering period spans July to September, it bridges midsummer into early autumn in wetter parts of the garden.
Growing conditions
Best soil and position for Lythrum
- Sunlight
- Full sun
- Soil type
- Sandy, Loamy, Clay
- Soil pH
- Neutral
- Soil moisture
- Moist but well-drained, Wet
- Aspect
- South-facing
- Exposure
- Sheltered
- UK hardiness
- H7
Plant details
Lythrum salicaria 'Robert' size, habit and characteristics
- Plant type
- Perennial
- Habit
- Clump forming
- Foliage
- Deciduous
- Height
- 1.0 m
- Suggested uses
- Borders, Water gardens, Wetland areas
- Native to
- Europe, Asia
Care notes
Pruning and caring for Lythrum salicaria 'Robert'
- Cultivation
- Prefers moist, fertile soil; tolerates wet conditions; can be invasive in some regions
- Pruning
- Cut back in late winter or early spring to encourage fresh growth
- Propagation
- By seed, division, or softwood cuttings
- Pest resistance
- Slugs, Snails
- Disease resistance
- Generally disease-free
Frequently asked questions
How do I grow Lythrum salicaria 'Robert'?
Prefers moist, fertile soil; tolerates wet conditions; can be invasive in some regions.
Where is the best place to plant Lythrum salicaria 'Robert'?
Lythrum salicaria 'Robert' prefers full sun. It suits sheltered positions.
What soil does Lythrum salicaria 'Robert' need?
Lythrum salicaria 'Robert' is adaptable and grows happily in most soil types, including sandy, loamy and clay. It prefers neutral soil. Aim for soil that stays moist but well-drained to wet.
How do I prune Lythrum salicaria 'Robert'?
Cut back in late winter or early spring to encourage fresh growth.
How big does Lythrum salicaria 'Robert' grow?
Lythrum salicaria 'Robert' reaches a height of 1.0 m.
Is Lythrum salicaria 'Robert' hardy in the UK?
Lythrum salicaria 'Robert' has an RHS hardiness rating of H7, meaning it is fully hardy throughout the UK, tolerating temperatures below -20°C.
How do I propagate Lythrum salicaria 'Robert'?
By seed, division, or softwood cuttings.
