Thalia dealbata
powdery alligator-flag
An evergreen, marginal aquatic perennial forming a clump of long-stalked, erect, narrowly ovate leaves to 40cm in length, covered with white powder, and slender stems bearing panicles of purple flowers 2cm across. Although not carnivorous as such, this plant may trap and kill small insects such as hoverflies and small bees during the pollination process.
Size
Ultimate height
1.5–2.5 metresTime to ultimate height
5–10 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Poorly–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green Grey Silver | |||
|---|---|---|---|---|
| Summer | Purple | Green Grey Silver | ||
| Autumn | Green Grey Silver | |||
| Winter | Green Grey Silver |
Position
- Full sun
Aspect
South–facing or West–facing or East–facing
Exposure
Sheltered Hardiness
H2Botanical details
- Family
- Marantaceae
- Native to the UK
- No
- Foliage
- Evergreen
- Habit
- Clump forming
- Genus
Thalia can be evergreen or deciduous perennials with long-stalked, lance-shaped leaves and long stems bearing violet-purple flowers in panicles
- Name status
Correct
- Plant range
- S US, Mexico
How to grow
Cultivation
Under glass, grow in baskets of loam based compost in full light. Grow as a marginal aquatic in a planting basket of fertile, loamy, humus-rich soil in up to 15cm of water at the edge of a sunny pool. In colder areas it will become deciduous. See pond plants for further advice
Propagation
Propagate by seed sown at 16-21°C, in moist seed compost, when ripe or in spring. Propagate by division in spring
Suggested planting locations and garden types
- Sub-tropical
Pruning
Remove old flowers and leaves regularly
Pests
Generally pest-free
Diseases
Generally disease-free
Get involved
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