Photo: Photo by David J. Stang, CC BY-SA 4.0 · source
Ornamental grass · Poaceae
Feather reed grass
Calamagrostis × acutiflora
In other languages: Struisriet (Nederlands) · Calamagrostide (Français)
Feather reed grass is an ornamental grass that arose from a cross between two European reed grasses. It forms a narrow, ramrod-straight clump of dark green leaves, with stiff plumes from June that are purplish-brown at first and later turn golden, like ripe wheat. In flower it reaches about 1.5–1.8 m tall but only 60 cm wide. ‘Karl Foerster’ is the best-known variety; ‘Overdam’ has white-striped leaves. It is one of the first grasses to start growing in spring and stays upright well into winter.
Light
Sun or partial shade
preferably some sun
Moisture
Normal to wet
must not dry out
Legal basis
Sand, loam or clay
any pH
Hardiness
Fully hardy
down to -30 °C
Size
1.6 m
tall, 0.6 m wide
Flowering
June–August
| Pruning months | February |
|---|---|
| Height | 1.6 m |
| Native to Belgium | No, planted |
| Poisonous to people and pets | Not known to be poisonous |
| Flowering | June–August |
Identify
Feather reed grass: how do you recognise it?
- Habit
- Narrow, upright clump; in flower 1.5–1.8 m tall and 60 cm wide.
- Leaves
- Dark green, narrow and linear; the leafy clump is 60–90 cm tall and starts growing early in spring.
- Plume
- Narrow and straight, from June; purplish-brown at first, later golden to straw-coloured.
- Roots
- A compact clump that widens slowly, without runners.
- Seed
- Produces no viable seed, so no seedlings.
Flowering: June–August · Plants: March–April and September–October · Pruning: February
In your garden
Why grow it?
- A strong vertical line in the border, from June into winter.
- Stays upright even in winter, lovely with frost or snow.
- Narrow: fits small gardens and looks good repeated in a rhythm or as a low hedge.
- Does not self-seed or spread.
- Not fussy: also does well on heavy, damp clay.
Feather reed grass: where does it grow best?
- Sun or light partial shade; in sun the stems stay sturdiest.
- Almost any soil: sand, loam or clay, acid to chalky.
- Moisture-retentive to damp: it copes with heavy, wet clay better than many other grasses.
- Plant 50–60 cm apart; in a row or hedge 40–50 cm apart.
- Light
- Sun and partial shade
- Soil type
- Sand, loam or clay
- Acidity
- Not fussy
- Moisture
- Normal or wet
- Size
- 1.6 m tall, 0.6 m wide
- Hardiness
- Hardy (to -30 °C)
Goes well with
- Purple coneflower: Round pink flowers against the straight lines.
- Salvia: Blue spikes at its feet in early summer.
- Sedum: Broad flower heads in late summer.
- Yarrow: Flat flower heads as a contrast to the upright plumes.
Maintenance
Feather reed grass: when and how to plant it?
Plant in March–April and September–October.
- Plant in March–April or in September–October.
- Dig a hole twice as wide as the rootball and mix in some compost.
- Set the clump at the same depth as in its pot and firm the soil well.
- Keep 50–60 cm between plants.
- Water in thoroughly, and in dry spells during the first year.
Care
- Watering
- In dry spells during the first year; after that little care. In very dry soil it stays smaller.
- Feeding
- A little compost in spring is enough.
- Mulching
- A layer of compost or leaf mould keeps the soil moist.
- Rejuvenating
- After a few years the centre may go bare: then divide the clump in spring.
Tip: Plant it in a row or repeat it a few times through the border: the stiff plumes bring calm and rhythm.
Feather reed grass: when to prune it?
Pruning months: February.
When: In late February, before new growth starts: it is an early riser.
How:
- Tie the clump together with string and cut it off in one go.
- Cut back to 10–15 cm above the ground.
- If green shoots are already showing, cut carefully above them.
Caution: Do not wait until April: you will cut off the young shoots too and the clump will look damaged for a while.
Propagation
- Division
- In March–April, as growth starts, or in September. Split the clump with a sharp spade and replant the pieces straight away.
Feather reed grass: how does it get through the winter?
Hardy to −30 °C.
- Fully hardy to −30 °C: no protection needed.
- Leave the plumes: they stay upright and look lovely with frost or snow.
- In a pot: stand it against a wall and make sure drainage is good.
Diseases and pests
- Rust: Orange-brown pustules on the leaves in a damp summer. Cut off affected leaves and give it an airy spot.
- Flopping: Too much shade or too rich a soil makes the stems fall open. Move it into sun and feed less.
- Stunted plant: In very dry soil it stays small. Water in dry summers and mulch.
- Bare centre: Older clumps go bare in the middle. Divide them in spring.
Through the year
- February: In late February, cut back to 10–15 cm.
- March: New growth. Plant or divide. Give compost.
- April: Plant or divide.
- May: Water young plants in dry spells.
- June: The first plumes appear, purplish-brown.
- July: The plumes turn golden.
- August: Plumes straw-coloured. Water in long droughts.
- September: Plant or divide.
- October: Plant. Leave the plumes standing.
- December: The upright stems decorate the winter garden.
You and this species
Did you know?
- Because it produces no viable seed, it never self-seeds.
- The variety ‘Karl Foerster’ is named after Karl Foerster (1874–1970), a German nurseryman who made ornamental grasses and perennials popular.
- It is a cool-season grass: it grows from early spring and flowers early in summer.