Pistia stratiotes
water lettuce
Although this plant is not listed on Schedule 9 of the UK Wildlife & Countryside Act as an invasive, non-native species, it is has been listed as a plant of concern. As of August 2024 it will be banned from sale in Northern Ireland. See cultivation notes for further details A tender, floating, evergreen aquatic perennial with semi-upright blue-yellow-green leaves. Inconspicuous tubular-shaped creamy-yellow flowers appear in the summer. May be invasive
Size
Ultimate height
0.1–0.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Colour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | ||||
|---|---|---|---|---|
| Summer | Cream Yellow | Green Grey Silver | ||
| Autumn | Green Grey Silver | Green | ||
| Winter |
Position
- Full sun
Aspect
South–facing or West–facing
Exposure
Sheltered Hardiness
H1BBotanical details
- Family
- Araceae
- Native to GB / Ireland
- No
- Foliage
- Evergreen
- Habit
- Floating
- Potentially harmful
- Harmful if eaten, skin/eye irritant. Wear gloves and other protective equipment when handling
- Genus
A genus of just one species of aquatic plant present in most tropical and sub-tropical fresh waterways due to both natural and human introduction. It is considered invasive and also offers a breeding ground for mosquitos. The rosettes of leaves are thick, soft and hairy and flowers pink-purple
- Name status
Correct
- Plant range
- Tropics
How to grow
Cultivation
This plant is listed on Schedule 9 of the UK Wildlife & Countryside Act as an invasive non-native species. Although not banned from sale, it is an offence to plant or cause these to grow in the wild IN ENGLAND, WALES, NORTHERN IRELAND and the REPUBLIC OF IRELAND. Gardeners possessing them should undertake measures to control them. See RHS advice on invasive non-native species for further information
Propagation
Please see cultivation notes
Suggested planting locations and garden types
Pruning
No pruning required
Pests
Generally pest-free
Diseases
Generally disease-free
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.