Switchgrass 'Northwind'

Sun

Full sun is best; light shade is tolerated, but stems may lean and flowering may be reduced.

Water

Water regularly during the first growing season. Once established, it tolerates dry spells but grows best with occasional deep watering during prolonged drought.

Soil

Adaptable to clay, loam and sandy soils, including moderately moist ground. Avoid permanently waterlogged soil, especially in winter, and very rich soil that encourages weak growth.

Height

4-6 ft (1.2-1.8 m), including flowers

Spread

2-3 ft (0.6-0.9 m)

Flowers

Late summer into autumn; fine, airy green flower panicles develop pinkish tones and mature to tan seedheads.

Foliage

Upright, relatively broad blue-green leaves turn golden yellow in autumn, then straw-coloured through winter. New growth emerges late in spring.

Growth

Moderate; usually forms a substantial clump within 2-3 growing seasons.

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

   2.7 ft (0.81 m)

3. After 2 years

   4 ft (1.3 m)

4. After 3 years

   5 ft (1.5 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 and Canada

Growth rate

Moderate

• Plant in full sun, allowing room for the mature clump rather than crowding it against neighbouring plants.
• Water deeply during dry spells in its first growing season; established clumps need much less attention.
• Avoid routine feeding and heavy applications of manure, which can make stems flop.
• Apply a light mulch after planting, keeping it clear of the crown.
• Divide in spring if the centre thins or the clump becomes too large; routine annual division is unnecessary.

Pruning. Leave the standing stems through winter, then cut the whole clump to 4-6 in (10-15 cm) above ground in late winter or early spring, before new shoots lengthen. Take care not to cut emerging green growth.

Late winter

Cut back last year's stems before fresh growth begins.

Spring

Plant container-grown plants as the soil warms; divide established clumps when new shoots appear.

Late spring

Check for new growth before assuming a dormant clump has died; switchgrass starts later than many border plants.

Summer

Water newly planted clumps during dry weather and avoid high-nitrogen feeding.

Late summer

Enjoy the flowers; remove unwanted seedlings nearby if any appear.

Autumn

Leave golden foliage and seedheads standing for winter structure and wildlife shelter.

• Repeat upright clumps through a perennial border to give rhythm among looser flowering plants.
• Plant in drifts with coneflowers, black-eyed Susans and asters for a prairie-style border.
• Use beside paths or terraces as a narrow, seasonal screen that remains visually light.
• Set against a dark hedge or wall to show off the fine flower panicles and golden autumn foliage.
• Combine with low, rounded plants in a contemporary garden for a clear contrast in shape.

Garden styles it suits: Architectural minimal, Modern, New perennial (prairie), Native meadow, Midwest prairie and Winter interest.

Plant it with: Purple coneflower, Black-eyed Susan, New England aster, Blazing star, Russian sage and Stonecrop.

Wildlife: The North American species supports several butterfly and moth larvae, and its seed can feed small birds. Standing clumps provide winter cover for insects and other small wildlife; the flowers are wind-pollinated rather than a significant nectar source.

• Flopping or leaning: move to a sunnier position and stop feeding; rich soil and shade weaken the upright habit.
• Rust or leaf spots: improve airflow, water at soil level and remove affected debris when cutting back; minor spotting rarely needs treatment.
• Crown rot in persistently wet soil: improve drainage or replant on slightly raised ground; discard badly rotted crowns.
• Thin or dead clump centre: lift and divide in spring, replanting healthy outer sections.

Switchgrass can poison horses and other grazing livestock if they eat enough foliage; saponins can cause liver damage and severe sensitivity to sunlight. It is not generally known to be toxic to cats, dogs or people under ordinary garden exposure, but it is not an edible plant and should not be offered as animal feed.

• Switchgrass 'Heavy Metal' (Panicum virgatum 'Heavy Metal')

  Usually shorter, with more distinctly metallic blue foliage; 'Northwind' has broader, more olive-blue leaves and a taller, strongly columnar habit.

• Feather reed grass 'Karl Foerster' (Calamagrostis × acutiflora 'Karl Foerster')

  Starts growing and flowering earlier, with narrow, dense flower spikes rather than switchgrass's open, airy panicles.

• Chinese silver grass (Miscanthus sinensis)

  Usually has more arching leaves with a conspicuous pale central stripe and fuller, silky flower plumes rather than fine, open panicles.

The species name virgatum means twiggy or wand-like, referring to the slender, upright stems.

Propagation. Divide in spring as growth begins, using a sharp spade or knife to separate rooted sections with several shoots. Division preserves 'Northwind'; seedlings do not reliably retain its upright form or other cultivar traits.

Accepted botanical name

Panicum virgatum

In the US and Canada

Native in Canada and the lower 48 states. Introduced in Hawaii.

Native range

Alabama, Arizona, Arkansas, Belize, Bermuda, Colorado, Connecticut, Cuba, Delaware, District of Columbia, Florida and Georgia.

Measured

Average height 100 cm.

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