Giant miscanthus
Miscanthus x giganteus ·
A huge, fountain-shaped grass, well over head height by midsummer, with broad, arching leaves that have a white midrib.
- Size
- 11½ ft tall, 5 ft wide
- Zones
- 4 to 9
- Light
- Full sun
- Flowers
- Grown for its leaves; flowers mid September to early November
- Pets
- Not checked
- Job in a bed
- Specimen
A bed built around giant miscanthus
The planner designed this bed around giant miscanthus when this page was made: a 16 × 8 ft (4.9 × 2.4 m) naturalistic planting in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why giant miscanthus stands where it does.
The plants
- 1 Giant miscanthus × 1, green leaves
- 2 Mazus × 33, lavender
- 3 Carpathian bellflower 'Blue Clips' × 8, blue
- 4 Sweet coneflower 'Henry Eilers' × 3, yellow
- 5 Siberian iris 'Caesar's Brother' × 3, purple
- 6 Gray's sedge × 3, green
- 7 Winter heath 'Kramer's Red' × 10, pink
- 8 Hyacinth × 8, white
- 9 Camassia × 4, blue
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
- The only bold leaves here. The rest are fine and medium. A change of leaf keeps plants distinct when nothing is in flower.
- Part of the bed's structure. Shrubs and grasses keep their shape when the perennials die down. So do Gray's sedge and winter heath 'Kramer's Red'.
Why here
- Anchors a back corner. At 11½ 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 Siberian iris 'Caesar's Brother' (3½ 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
- Here for its leaves, spring to frost. They cover the 10 weeks between early March and late November when nothing 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 naturalistic planting: low grasses and groundcovers, the matrix, make up 60% of the planted ground. Giant miscanthus and sweet coneflower 'Henry Eilers' anchor the back corners of the bed: the tallest plants on the plan stand there. Mazus repeats along the bed to tie it together.
The planner's own design check: 11 Excellent, 5 Good, 1 Needs revision. Its weakest point is height and scale: Heights average about 6 in at the front, 20 in in the middle and 4½ ft at the back. Along the back row the heights step up and down, between 2½ ft and 11½ ft, and no two neighbours are the same height. 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 giant miscanthus goes in a border
At 11½ ft it belongs at the back of a bed. In the planner's ten height classes it is super tall (over 6½ 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.
A sterile hybrid, so it cannot seed into wild land as other maiden grasses do. It makes a summer screen in one season, and is grown as a biomass crop.
- A seasonal screen
- A giant specimen
- The back of a very large border
What to plant with giant miscanthus
Plants recorded as good partners for it, and what each pairing does:
- Joe Pye weed 'Gateway': adds the flowers, late July to mid September; low enough (6 ft) to stand in front of it; happy in the same moist soil.
- New York ironweed: adds the flowers, early August to mid September; medium leaves against its bold ones; low enough (6½ ft) to stand in front of it.
- Giant coneflower: adds the flowers, late June to early August; low enough (6 ft) to stand in front of it.
Questions about giant miscanthus
Does giant miscanthus need sun or shade?
Giant miscanthus 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 giant miscanthus grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should giant miscanthus be planted?
4 ft (120 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 5 ft (150 cm), so a group knits into one patch.
It grows 11½ ft (350 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many giant miscanthus plants do I need?
Usually one. At 4 ft (120 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 4 ft apart: three plants for a 10 ft run.
In the bed above, the planner used one in one group.
What does giant miscanthus look like in winter?
Giant miscanthus 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'
- Flame grass Miscanthus 'Purpurascens'
- Maiden grass 'Gracillimus' Miscanthus sinensis 'Gracillimus'
- Maiden grass 'Morning Light' Miscanthus sinensis 'Morning Light'
- Zebra grass Miscanthus sinensis 'Zebrinus'
In these guides
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Grass
- Size
- 11½ ft (350 cm) tall, 5 ft (150 cm) wide
- Plant
- 4 ft (120 cm) apart
- Height class
- Super tall (over 6½ ft)
- Place in the bed
- Back
- Flowers
- Mid September to early November; feathery plumes; tan, pink
- Leaves
- Bold texture, herbaceous; green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 to 9
- Light
- Full sun
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- None needed
Not yet checked against an outside reference: its figures rest on general horticultural knowledge. 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.