Giant feather grass

Sun

Full sun; flowering is weaker and stems may lean in shade.

Water

Water regularly during the first growing season, allowing the soil surface to dry between waterings. Established plants tolerate drought and need extra water mainly during prolonged dry spells.

Soil

Well-drained soil, including sandy, gravelly or chalky ground. Tolerates a range of pH levels; avoid waterlogged soil, especially in winter.

Height

6-8 ft (1.8-2.4 m) in flower; foliage usually 1.5-2.5 ft (0.45-0.75 m)

Spread

2-4 ft (0.6-1.2 m)

Flowers

Late spring to midsummer: airy sprays of oat-like spikelets, initially greenish with purple tones, becoming straw-gold and persisting into autumn.

Foliage

Narrow, arching, grey-green leaves form a dense basal mound. Usually evergreen in mild climates, but foliage may brown in cold winters.

Growth

Moderate; allow two or three growing seasons for a substantial flowering clump.

Care needed

Low

• Deer resistant
• Drought tolerant
• Heat tolerant
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.1 ft (0.35 m)

2. After 1 year

   3 ft (1.1 m)

3. After 2 years

   6 ft (1.8 m)

4. After 3 years

   7 ft (2.1 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Plant in full sun with the crown at soil level and plenty of room for the arching flower stems.
• Water deeply during establishment, then reduce watering once roots are well developed.
• Avoid rich feeding; on poor soil, give a light application of balanced fertiliser in spring.
• Keep mulch away from the crown and improve drainage before planting in heavy soil.
• Leave established clumps undisturbed unless they become congested or develop a dead centre.

Pruning. In early spring, wear gloves and comb or rake out dead leaves, then cut old flowering stems down near their base. Do not routinely shear the whole evergreen mound to ground level; remove winter-damaged foliage selectively.

Early spring

Remove dead leaves and old flowering stems before fresh growth becomes crowded.

Spring

Plant new specimens or divide congested mature clumps as active growth begins.

Late spring

Check newly planted clumps for dry soil and water deeply when needed.

Summer

Leave flower sprays to ripen to gold; cut a few for drying if wanted.

Autumn

Retain sound seed heads for structure, or remove them before seed falls if unwanted seedlings appear.

Winter

Keep the crown free of wet leaf litter and check that surrounding soil drains freely.

• Place near the middle or back of a sunny border, where the transparent flower sprays rise above lower perennials.
• Plant where morning or evening sun shines through the golden seed heads.
• Use repeated clumps in gravel gardens with lavender, sage and other drought-tolerant plants.
• Combine with bold flower shapes such as alliums and sea hollies for contrast with its fine stems.

Garden styles it suits: Dry gravel garden, Mediterranean, New perennial (prairie), Architectural minimal, Modern rustic and Low-maintenance.

Plant it with: English lavender, Russian sage, Purpletop vervain, Ornamental onions, Yarrow and Sea holly.

Wildlife: The foliage and retained stems offer shelter for small invertebrates. Flowers are wind-pollinated and are not a useful nectar source for bees.

• Crown rot in wet soil: improve drainage or move the plant to a raised, freely draining position; remove badly rotted clumps.
• Few flowers or leaning stems: move to full sun and avoid heavy feeding or excessive watering.
• Winter-browned foliage: leave protective growth in place until spring, then remove damaged leaves without cutting healthy green growth.
• A dead centre in an old clump: divide in spring and replant vigorous outer sections.

Not known to be toxic to people, cats, dogs or horses. No poisonous part is recognised, but dry, awned seed heads can cause mechanical irritation or lodge in an animal's coat, eyes or mouth.

• Mexican feather grass (Nassella tenuissima)

  Much smaller, with extremely fine, hair-like leaves and soft, feathery flower heads rather than tall sprays of distinct oat-like spikelets.

• Golden oat grass (Stipa ichu)

  Has narrower, more upright, silvery flower plumes rather than the broad, open, golden oat-like sprays of giant feather grass.

• Tufted hair grass (Deschampsia cespitosa)

  Produces a finer cloud of tiny spikelets, generally on shorter stems, and prefers more moisture than giant feather grass.

The epithet gigantea means giant, referring to the plant's unusually tall flowering stems.

Propagation. Divide established clumps in spring, keeping substantial pieces with healthy roots and shoots; mature clumps can be difficult to split. Alternatively, sow ripe seed in pots of freely draining seed compost; seedlings take time to reach flowering size.

Accepted botanical name

Celtica gigantea

Native range

Morocco, Portugal and Spain.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.