Wavy hair grass

Sun

Full sun to partial shade; light shade is helpful in warmer climates.

Water

Water regularly while establishing; established plants tolerate moderately dry soil but not prolonged drought in hot weather.

Soil

Well-drained, acidic to neutral soil of low to moderate fertility; particularly suited to sandy, gravelly or peaty ground. Avoid waterlogged soil and strongly alkaline conditions.

Height

1-3 ft (0.3-0.9 m), including flower stems

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring to summer; tiny purplish-green flowers in open, shimmering panicles, fading to pale straw.

Foliage

Very fine, dark green, rolled leaves form soft, arching tufts; usually evergreen, but foliage can brown in severe cold or drought.

Growth

Moderate

Care needed

Low

• Deer resistant
• Cold hardy
• Wildlife

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

Difficulty

Easy

Toughness

Fairly tough

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

1. Planting day

   1.1 ft (0.35 m)

2. After 1 year

   1.5 ft (0.45 m)

3. After 2 years

   1.8 ft (0.55 m)

4. After 3 years

   2 ft (0.6 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

Native to

the US, Canada and the UK

Invasive in

Australia

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Moderate

• Water during the first growing season whenever the root zone dries out.
• Avoid routine feeding; rich soil encourages loose growth and leaning flower stems.
• Keep the crown clear of thick mulch and standing water.
• Divide congested or thinning clumps in spring and replant the vigorous outer sections.
• Remove flower stems before seed falls if unwanted seedlings appear.

Pruning. In late winter or early spring, comb out dead leaves and cut old flower stems near the base. Trim badly browned foliage lightly rather than routinely cutting the whole evergreen tuft to the ground.

Early spring

Remove dead foliage and old stems before fresh growth develops.

Spring

Plant or divide clumps, then water thoroughly.

Late spring

Check new plants for dry soil as flower stems begin to rise.

Summer

Water during extended dry spells and remove seed heads if seedlings are unwanted.

Autumn

Leave sound seed heads for texture, or remove them where self-seeding is a concern.

Winter

Check that fallen leaves and wet mulch are not smothering the crowns.

• Plant in loose groups along lightly shaded woodland edges for a fine-textured foreground.
• Thread through naturalistic perennial planting to create a transparent layer of flowers.
• Combine with heathers and other acid-soil plants on well-drained ground.
• Use beside paths where low foliage stays unobtrusive and flower stems catch the light.

Garden styles it suits: Woodland, New perennial (prairie), Wildlife garden, Low-maintenance, Modern rustic and Sensory garden.

Plant it with: Heather, Bilberry, Foxglove, Hard fern, Rowan and Silver birch.

Wildlife: Provides shelter for small invertebrates, and its seeds may be eaten by birds. Flowers are wind-pollinated rather than a significant nectar source.

• Crown rot in wet ground: improve drainage or move the plant, keeping the crown at soil level.
• Loose, flopping growth in rich soil or deep shade: stop feeding and move to a brighter, leaner site.
• Brown foliage during hot droughts: water deeply during prolonged dry weather and provide light afternoon shade in hot regions.
• Unwanted seedlings: remove flower heads before seed ripens and pull young seedlings promptly.

Not known to be toxic to people, cats, dogs or horses. No part is generally recognised as poisonous, but this ornamental grass should not be treated as food or as a substitute for suitable horse pasture.

Where it spreads. Can self-seed freely on open, acidic ground. It is introduced and naturalised in south-eastern Australia, including Victoria and Tasmania, where it can spread into native vegetation; check local environmental weed advice before planting.

• Tufted hair grass (Deschampsia cespitosa)

  Usually forms a larger, coarser tussock with broader, flat, rough leaves; wavy hair grass has very fine, rolled leaves and more noticeably winding flower branches.

• Purple moor grass (Molinia caerulea)

  Has broader, flat leaves and flowers later, usually from midsummer into autumn; its foliage turns golden and dies back rather than remaining green through winter.

• Sheep's fescue (Festuca ovina)

  Also has fine, rolled leaves, but its flower heads are narrower and more compact, without the broad, airy panicles and winding branches.

The species name flexuosa means winding or bent, referring to the sinuous flower branches that also give rise to the common name.

Propagation. Divide established clumps in spring, or sow seed in autumn or spring. Seed-grown plants vary, so divide named selections to preserve their characteristics.

Accepted botanical name

Avenella flexuosa

In the US and Canada

Native in Canada, Greenland, the lower 48 states and St. Pierre and Miquelon. Introduced in Alaska.

Native range

Alabama, Albania, Algeria, Argentina Northeast, Argentina Northwest, Argentina South, Arkansas, Austria, Baltic States, Belarus, Belgium and Borneo.

Measured

Soil pH 4.8 to 6.8. Average height 13 cm.

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