Big bluestem

Sun

Full sun; tolerates light shade but becomes looser and more likely to lean.

Water

Water regularly during establishment. Established plants tolerate drought, although prolonged dry conditions reduce height and flowering.

Soil

Adaptable to sandy, loamy or clay soils, provided they are not persistently waterlogged. Lean to moderately fertile soil produces sturdier growth than rich, heavily fed soil.

Height

4-8 ft (1.2-2.4 m)

Spread

2-3 ft (0.6-0.9 m) initially; colonies can become wider over time

Flowers

Late summer to early autumn; small purplish to bronze flowers on finger-like branches, usually arranged in groups of three.

Foliage

Narrow green to blue-green leaves on upright stems, turning orange, copper, reddish purple or bronze in autumn, then straw-coloured in winter.

Growth

Moderate; slow to start in spring, then grows strongly in summer.

Care needed

Low

• Deer resistant
• Drought tolerant
• Cold hardy
• 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

   2.6 ft (0.8 m)

3. After 2 years

   4 ft (1.2 m)

4. After 3 years

   6 ft (1.7 m)

5. After 5 years

   6 ft (1.8 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

Canada

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Slow

• Plant in full sun with enough room for its mature height and spreading base.
• Water deeply during the first growing season, allowing the surface soil to dry between waterings.
• Avoid routine feeding; excess nitrogen encourages tall, floppy stems.
• Keep mulch thin and away from the crown, especially on heavy soil.
• Divide in spring if the clump becomes too large, and remove unwanted seedlings while small.

Pruning. Leave stems standing through winter, then cut them to 4-6 in (10-15 cm) above ground in late winter or early spring before new shoots lengthen. Remove broken stems sooner if they fall across paths.

Late winter

Cut down old stems before new growth starts; check first for overwintering wildlife.

Spring

Plant or divide as the soil warms and new shoots appear.

Late spring

Weed around emerging shoots; this warm-season grass starts later than many border plants.

Summer

Water new plants during dry spells; established clumps usually need little supplementary watering.

Early autumn

Collect ripe seed if wanted, or remove seed heads where seedlings would be unwelcome.

Late autumn

Leave upright stems and seed heads for winter structure and wildlife.

• Plant in broad groups with coneflowers and black-eyed Susans for a prairie-style border.
• Use behind shorter perennials to provide a tall, seasonal backdrop.
• Repeat clumps through a large naturalistic planting to link late-season flowers.
• Place where low autumn light can catch the coloured leaves and winter stems.

Garden styles it suits: Native meadow, New perennial (prairie), Midwest prairie, Wildlife garden, Autumn colour and Winter interest.

Plant it with: Purple coneflower, Black-eyed Susan, Rough blazing star, Butterfly weed, Wild bergamot and New England aster.

Wildlife: In its North American native range, the foliage feeds several skipper butterfly larvae. Clumps provide cover for insects and small animals, and some birds eat the seeds. Wind-pollinated flowers offer little direct value to nectar-feeding insects.

• Flopping stems: provide full sun, avoid fertiliser and move plants out of excessively rich soil; discreetly support established clumps if necessary.
• Rust or leaf spots: improve airflow, avoid wetting foliage repeatedly and remove badly affected leaves; treatment is rarely needed.
• Crown decline in wet soil: improve drainage or move the plant to a site without prolonged winter waterlogging.
• Unwanted spread: lift encroaching rhizomes in spring and remove seedlings or cut seed heads before seed falls.

Not known to be toxic to cats, dogs, horses or people. The leaves and stems are used as livestock forage; no part is recognised as poisonous under normal garden conditions.

Where it spreads. Can spread strongly by short rhizomes and seed in favourable garden conditions, including within its native range in the central and eastern United States and southern Canada. This local spread is not the same as being a listed invasive species.

• Little bluestem (Schizachyrium scoparium)

  Usually shorter and more finely textured, with fluffy white seeds along slender stems rather than the conspicuous turkeyfoot seed heads of big bluestem.

• Indiangrass (Sorghastrum nutans)

  Has dense, golden-brown, plume-like flower heads rather than several finger-like branches.

• Switchgrass (Panicum virgatum)

  Produces broad, airy clouds of tiny flowers and seeds rather than narrow, forked seed heads.

Andropogon comes from Greek words meaning 'man's beard', referring to the hairy spikelets, while the species name honours the French botanist Louis Gérard.

Propagation. Divide established clumps in spring as growth begins. Sow species seed in spring following the supplier's pretreatment instructions; a period of cold, moist conditions can improve germination. Seed-grown plants vary, and named cultivars should be divided to retain their characteristics.

Accepted botanical name

Andropogon gerardi

Native range

Alabama, Arizona, Arkansas, Belize, Connecticut, Colorado, Costa Rica, Delaware, El Salvador, Florida, Georgia and Honduras.

Measured

Average height 68 cm.

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