Giant feather grass

Giant feather grass: how do you recognise it?

Habit

Dense evergreen tussock 60–70 cm tall and about 1 m across; flowering stems up to 2 m.

Leaves

Narrow, rolled and grey-green, stiff and slightly arching.

Flowers

From June to August, large open panicles of oat-like spikelets with long awns; purplish at first, then golden yellow.

Stems

Sturdy and stiff; they stand for a long time and turn straw-coloured.

Roots

Deep and fibrous; a large clump does not transplant well.

Flowering: June–August · Plants: April–May · Pruning: March–April

Why grow it?

• Spectacular golden plumes up to 2 m tall, from June until late summer.
• See-through: you look through the plumes, so it can even go at the front of a border.
• Evergreen and drought-tolerant: once established it hardly needs any water.
• The plumes catch the morning and evening light and move in every breeze.
• The stems look good in large arrangements and dried bouquets.
• An eye-catcher as a specimen in a gravel garden or prairie-style planting.

Giant feather grass: where does it grow best?

• Full sun, the warmest spot you have.
• Well-drained sandy or loamy soil, neutral to chalky; on wet, heavy clay it dwindles.
• Dry to normally moist soil: once established it tolerates long droughts.
• Give it about 1 m across, with low plants around it so the tussock stays visible.
• At its best against a dark background or backlit by the evening sun.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

2 m tall, 1 m wide

Hardiness

Hardy (to -15 °C)

Goes well with

• Lavender: Low purple flowers at the base, for the same dry, sunny spot.
• Coneflower: Sturdy late-summer flowers beneath the golden plumes.
• Globe thistle: Blue globes in July–August, also drought-tolerant.
• Catmint: A soft sea of blue flowers around the base of the tussock.
• Purpletop vervain: Purple flowers on long, thin stems that weave attractively through the plumes.

Giant feather grass: when and how to plant it?

Plant in April–May.

1. Plant in April–May, as the soil warms up; planted in autumn it copes badly with a wet winter.
2. Dig a generous hole and mix coarse sand or gravel into heavy soil; no manure.
3. Set the tussock at the same depth as it was in the pot, no deeper.
4. Allow about 1 m between plants or between the tussock and its neighbours.
5. Water in well and water in dry spells during the first season.
6. If you like, mulch with gravel rather than compost: that keeps the crown dry.

Care

Water

Only in dry spells during the first year. After that it is not needed, except in a pot.

Feeding

Not needed: on poor soil the stems stay sturdier.

Tidying

In March–April, pull the dead leaves out of the tussock with gloved hands.

Flower stems

Leave them as long as they look good; cut them off at the base when they collapse, by March at the latest.

Patience

In the first year after planting it often flowers little; from the second year it comes into its own.

Tip: Plant it where the low morning or evening sun shines through the plumes, and in spring just pull the dead leaves out of the tussock instead of cutting it.

Giant feather grass: when to prune it?

Pruning months: March–April.

When: Do not cut back: in March–April just pull the dead leaves out of the tussock and cut off the old flower stems.

How:

• In March–April, pull the dead grey leaves out of the tussock, wearing gloves; they come away easily.
• Cut old flower stems off low down by the tussock when they no longer look good.
• A fine-toothed rake helps to comb out a large tussock.

Caution: Do not cut the tussock short like other grasses: it weakens the plant and can make the centre die.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

In spring, in small pots of seed compost, lightly covered and placed somewhere light and warm. Only plant the young plants out the following spring.

Division

Possible in May, as growth starts, but large clumps are hard to split and slow to re-establish. Take pieces with plenty of roots and give them extra water.

Giant feather grass: how does it get through the winter?

Hardy to −15 °C: protect young plants.

• Hardy to about −15 °C: no problem in most Belgian winters on free-draining soil.
• Wet soil in winter is more dangerous than frost: make sure drainage is good.
• The grey-green leaves remain; the straw-coloured flower stems often decorate the garden well into autumn.
• In a large pot: stand it in a sheltered spot against a wall, out of the rain, and keep it fairly dry in winter.

Diseases and pests

• Rotting centre: The middle of the tussock turns brown and limp, often after a wet winter or after being cut short. Improve the drainage and do not cut the tussock back.
• Few plumes: Too little sun, soil that is too rich or a plant that is too young. Give it the sunniest spot and no fertiliser.
• Collapsing stems: After heavy rain or wind. On poor, free-draining soil they stay sturdier; cut off broken stems.
• Bare centre: In older plants the centre dies off. In May, split off the living pieces from the edge and replant them.

Through the year

• March: Pull out dead leaves. Cut off old flower stems.
• April: Pull out dead leaves. Plant.
• May: Plant or divide. The flower stems appear.
• June: Flowering: purplish plumes.
• July: Golden plumes. Cut stems for a vase.
• August: Flowering. Water only young plants in dry spells.
• September: Straw-coloured plumes in the autumn light.
• November: Leave the stems standing as long as they look good.
• December: Evergreen tussock. Do not cut back.

Did you know?

• Botanists have moved it from the genus Stipa to a genus of its own, Celtica; in garden centres it is still usually called Stipa gigantea.
• ‘Gigantea’ refers to the flower stems: the leaves stay low, but the plumes reach about 2 m.
• In English it is also called golden oats, because the spikelets look like oats.