Flame grass
Miscanthus 'Purpurascens' ·
An upright grass whose leaves turn brilliant orange-red in autumn, earlier and brighter than any other, with silvery-white plumes from late summer.
- Size
- 4½ ft tall, 3½ ft wide
- Zones
- 4 to 8
- Light
- Full sun
- Flowers
- Early August to mid September
- Pets
- No toxicity recorded
- Job in a bed
- Specimen
A bed built around flame grass
The planner designed this bed around flame grass when this page was made: a 12 × 6 ft (3.7 × 1.8 m) contemporary bed in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why flame grass stands where it does.
The plants
- 1 Flame grass × 1, white
- 2 Striped bloody cranesbill × 4, pink
- 3 Mouse-ear coreopsis 'Nana' × 8, yellow
- 4 Siberian iris 'Caesar's Brother' × 3, purple
- 5 Garden phlox 'Bright Eyes' × 3, pink
- 6 Lady's mantle × 3, green
- 7 Red spider lily × 8, red
Why this plant
- The bed's only structure. Shrubs and grasses keep their shape when the perennials die down, and it is the only one here.
- The only plumes. The others are open bowls, daisies, dense clusters and others. Shape reads at a distance, where colours blur.
- The only white. White sits between stronger colours and calms them.
Why here
- Anchors a back corner. At 4½ ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to garden phlox 'Bright Eyes' (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A feature plant is seen as an object, and needs clear ground around it.
Why now
- In flower for 7 weeks. From early August to mid September.
- Fills a gap. For one of those weeks nothing else on the plan is in flower.
- Stands through winter. Left uncut, it holds its shape until March, when the perennials have gone.
Planned as a contemporary bed: 28 of the 28 plants that stand in groups (100%) are set out in a pattern with their neighbours: a straight row, a triangle, or five like the five on a dice. Flame grass and Siberian iris 'Caesar's Brother' anchor the back corners of the bed: the tallest plants on the plan stand there. The bed is balanced: the left half carries 47% of the visual weight and the right half 53%.
The planner's own design check: 10 Excellent, 6 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where flame grass goes in a border
At 4½ ft it belongs at the back of a bed. In the planner's ten height classes it is tall (4 to 5 ft).
Its job: specimen. A feature plant with a shape of its own. It stands alone with room around it, and repeats only at a distance.
It is hardier than the maiden grasses and rarely sets viable seed, so it does not share their invasive habit. It needs moisture; in dry soil the colour is poor.
- The best autumn colour of any grass
- Cold-climate gardens
- Moist borders
What to plant with flame grass
Plants recorded as good partners for it, and what each pairing does:
- New England aster: in flower together for three weeks, from early September; happy in the same moist soil.
- Joe Pye weed 'Gateway': in flower together for six weeks, from early August; bold leaves against its medium ones; happy in the same moist soil.
- Black-eyed Susan: in flower together for seven weeks, from early August; low enough (24 in) to stand in front of it.
Questions about flame grass
Does flame grass need sun or shade?
Flame grass grows in full sun (6 or more hours of direct sun a day).
It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells.
What zones does flame grass grow in?
USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does flame grass flower in my zone?
In zone 5 it flowers early August to mid September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 4 | Mid August to mid September |
|---|---|
| Zone 5 | Early August to mid September |
| Zone 6 | Early August to mid September |
| Zone 7 | Early August to mid September |
| Zone 8 | Early August to mid September |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should flame grass be planted?
3 ft (90 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3½ ft (100 cm), so a group knits into one patch.
It grows 4½ ft (140 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many flame grass plants do I need?
At 3 ft apart, set out in staggered rows:
- 1 to fill 10 square feet (about 1 m²)
- 4 for a single row 10 ft (3 m) long
- 4 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one, with clear ground around it: a feature plant is seen as an object, and a group of them is a thicket.
In the bed above, the planner used one in one group.
Is flame grass poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like flame grass?
Flame grass is not native to North America. These North American natives come closest to doing its job:
- Switchgrass 'Cloud Nine': the same job in a bed and the same flowering time; 2½ ft taller, pink, not white.
- Hardy hibiscus: the same job in a bed, the same size, the same flowering time and the same colour; bold leaves, not medium.
- New York ironweed: the same job in a bed and the same flowering time; 24 in taller, 6 in narrower.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
What flowers after flame grass?
Flame grass is over by mid September. These start as it finishes and carry the same spot on, so it never goes flat:
- Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
- Montauk daisy: from mid September to late October, 3 ft tall, to stand in front of it and cover its fading stems.
- Calico aster 'Lady in Black': from mid September to mid October, 3½ ft tall, to stand in front of it and cover its fading stems.
What does flame grass look like in winter?
Flame grass turns the colour of straw and, left uncut, stands through the winter. Cut it down in late winter, before the new shoots come up.
More Miscanthus
- Dwarf maiden grass 'Adagio' Miscanthus sinensis 'Adagio'
- Giant miscanthus Miscanthus x giganteus
- Maiden grass 'Gracillimus' Miscanthus sinensis 'Gracillimus'
- Maiden grass 'Morning Light' Miscanthus sinensis 'Morning Light'
- Zebra grass Miscanthus sinensis 'Zebrinus'
In these guides
- Pet-safe plants for a sunny border
- Tall perennials and grasses for the back of a border
- Plants for a white garden
- Plants with purple and burgundy leaves
Every fact on record
- Type
- Grass
- Size
- 4½ ft (140 cm) tall, 3½ ft (100 cm) wide
- Plant
- 3 ft (90 cm) apart
- Height class
- Tall (4 to 5 ft)
- Place in the bed
- Back
- Flowers
- Early August to mid September; feathery plumes; white
- Leaves
- Medium texture, herbaceous; green, red
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.