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Plant Profiles / Purple fountain grass
Photos: Wikimedia Commons
Purple fountain grass
Cenchrus setaceus 'Rubrum' · Red fountain grass
Burgundy-purple arching leaves and soft, bottlebrush plumes from summer to autumn. A dramatic, fast filler for sunny pots.
Full sunLight
WeeklyWater
EasyCare level
Care at a glance
Light
Full sun
ShadeFull sun
Full sun for the deepest burgundy colour.
Water
Weekly
DryWet
Drought tolerant once established; pots need regular water in summer.
Humidity
Any
LowHigh
Adaptable.
Temperature
Frost tender, 5–40°C (41–104°F)
CoolWarm
Treat as an annual where winters drop below about -5°C (23°F).
Growth
Fast, arching
SlowFast
Grows 90–120 cm tall and wide.
Soil
Well-drained
LeanRich
Adapts to most soils.
Fertiliser
Light, spring
RarelyOften
A light slow-release feed in spring.
Pet safety
Non-toxic
SafeToxic
Considered non-toxic to cats and dogs.
About this plant
'Rubrum' is a sterile form of fountain grass, so it doesn't self-seed like the green species, which can be invasive. It's frost tender and often grown as an annual in cold climates. In warm areas it can stay perennial.
Best spots
Sunny balconies, large pots, borders and poolside plantings.
Plant facts
| Botanical name | Cenchrus setaceus 'Rubrum' |
| Family | Poaceae |
| Origin | Africa & Middle East (species) |
| Plant type | Tender perennial grass |
| Mature size | 90–120 cm |
| Growth rate | Fast |
| Foliage | Arching burgundy blades |
| Flowers | Soft purple bottlebrush plumes |
| Toxicity | Non-toxic to pets |
| Propagation | Division |
Seasonal care calendar
J
F
M
A
M
J
J
A
S
O
N
D
Active growth
Flowering
Cut back
Plant
Active growthFloweringCut backPlant
Based on Southern Hemisphere seasons.
Troubleshooting
| Green leaves | Not enough sun. |
| Dies over winter | Frost. Grow in pots and protect, or replant. |
| Brown tips | Underwatering in pots. |
| Flat, messy clump | Cut back in late winter. |
| Few plumes | Too much shade. |
Common questions
Is it invasive?
'Rubrum' is sterile and doesn't self-seed. Check your local rules for the green species.
Will it survive winter?
Only in mild climates; protect from frost.
When should I cut it back?
In late winter, to about 15 cm.
Can it grow in a pot?
Yes, it's a great pot plant.
