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Austrostipa spp.

speargrasses

Poaceae

Australia (with a few species in New Zealand)

Drought Tolerant

SunFull Sun

WaterVery Low · drought-tolerant

HardinessZones 8–10

Overview

Austrostipa spp. is a genus of about 60 to 65 species of perennial tussock grasses in the family Poaceae, almost all native to Australia with a few reaching New Zealand. Known as speargrasses or corkscrew grasses, they form dense clumps of narrow, often inrolled leaves and send up flowering stems 1 to 6.5 feet (0.3 to 2 m) tall. The flowerheads are open or narrow panicles bearing single-flowered spikelets, each seed tipped with a long, bent and twisted awn 1 to 6 inches (2.5 to 15 cm) long. As the awn dries and wets it coils and uncoils, driving the sharp-pointed seed into the soil or into animal hair. Leaves are green to grey-green and many species cure to straw colour over summer. The genus is widespread across Australian grasslands, woodlands, and semi-arid shrublands, where the grasses are major components of native pasture. They are deep-rooted and tolerate extended drought, poor soils, and heat. The penetrating awned seeds can lodge in the eyes, mouths, and skin of grazing stock and reduce wool value, which limits their use near livestock. Several species are grown in dryland and native gardens for their slender, airy flowering stems.

Native Range

Austrostipa spp. is almost entirely Australian, occurring in every mainland state across grasslands, open woodlands, and semi-arid country. A small number of species extend to New Zealand. The genus is absent as a native from North America.

Suggested Uses

Speargrasses are used in dryland, native, and revegetation plantings across Australia, where they bind light soils and are grazed by stock. The airy seed heads catch low light in meadow-style plantings. Their penetrating seeds are a drawback near paths, pets, and livestock yards.

How to Identify

Look for dense perennial tussocks of narrow, often inrolled leaves topped by airy panicles. Each seed carries a long, twice-bent awn 1 to 6 inches (2.5 to 15 cm) long that twists like a corkscrew when dry. The sharp, hardened seed base and the long coiling awn separate Austrostipa spp. from most other native tussock grasses, though microscopic detail of the lemma is sometimes needed to confirm the species.

Appearance

Size & Dimensions

Height1' - 6'6"

Width/Spread1' - 3'

Colors

Flower Colors

brown

Foliage Colors

green

Bloom Information

Bloom Period

~10 weeks

Spring Summer

Flowering stems are produced mainly in spring and early summer, roughly September to December in the southern hemisphere, with timing shifting earlier in warmer inland areas. The panicles and their long awns persist into summer as the seed matures. Plants often flower in response to winter and spring rainfall.

Detailed Descriptions

Flower Description

Straw to golden brown

Foliage Description

Green to grey-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 8.0(Neutral)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Very Low

Frost Tolerance

hardy

Time to Maturity

Forms a flowering clump in 2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Most species grow in full sun on light, free-draining soils and are well adapted to drought, heat, and low fertility. They are deep-rooted perennials that need no irrigation once established and dislike waterlogged ground. A broad soil pH from about 5.0 to 8.0 is tolerated. The tussocks are evergreen but the flowering stems and older leaves dry to straw colour and can be cut or raked out. Plants regenerate from the base and from self-sown seed. Few pests trouble them, though the awned seeds can be a nuisance where they catch in clothing or animal coats.

Pruning

Old flowering stems and dead leaf matter can be trimmed or combed out in late summer or autumn after seed has shed. Some growers cut clumps back hard every few years to renew fresh foliage. No other routine pruning is needed.