Purple fountain grass

Sun

Full sun gives the strongest leaf colour and best flowering; light shade produces greener, looser growth.

Water

Water regularly while establishing, then when the soil begins to dry. Established plants tolerate short dry spells, but containers need more frequent watering.

Soil

Well-drained soil of average fertility; tolerates sandy or loamy ground but dislikes waterlogged clay, especially in winter.

Height

3-5 ft (0.9-1.5 m), including flower plumes

Spread

2-3 ft (0.6-0.9 m)

Flowers

Summer to autumn; pink-purple, bristly plumes fade to buff as they age.

Foliage

Narrow, arching burgundy to reddish-purple blades; colour is strongest in sun. Foliage may persist in frost-free climates but dies back or is killed by frost.

Growth

Fast in warm weather; can reach flowering size in one growing season.

Care needed

Low

• Deer resistant
• Drought tolerant
• Heat tolerant

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

   2.9 ft (0.87 m)

3. After 2 years

   4 ft (1.2 m)

   full size

About 2 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

Fast

• Plant after frost danger has passed and the soil has warmed.
• Water new plants deeply when the upper soil begins to dry; check pots frequently during hot weather.
• Apply a light feed in spring; avoid heavy nitrogen feeding, which encourages floppy growth.
• Use containers with drainage holes and keep the crown out of standing water.
• Where winters are cold, replace plants annually or move a potted plant into a bright, frost-free place before frost.

Pruning. Where plants survive winter, cut old foliage to 4-6 in (10-15 cm) above ground in late winter or early spring, before new shoots lengthen. In cold climates, remove frost-killed plants unless you are overwintering them indoors.

Early spring

Cut back overwintered outdoor clumps before new growth starts; keep sheltered plants bright and only lightly watered.

Late spring

Plant out after the last frost once the soil is warm, gradually acclimatising plants raised under cover.

Early summer

Water developing clumps during dry spells and give container plants a light feed.

Summer

Check pots frequently for drying and leave developing plumes for their colour and movement.

Early autumn

Move any plants you want to save into bright, frost-free shelter before cold nights arrive.

Late autumn

Remove frost-killed annual plants, or leave standing foliage on surviving outdoor clumps until late winter.

• Use as the tall centrepiece in a large sunny container, with trailing plants around the rim.
• Repeat clumps through a hot-coloured border with orange, red or yellow flowers.
• Plant against pale paving or walls to show off the dark foliage and arching outline.
• Combine with broad-leaved cannas for a contrast of fine and bold textures.

Garden styles it suits: Modern, Architectural minimal, Hot border, Tropical, Modern courtyard and Sensory garden.

Plant it with: Canna, Dahlia, Zinnia, Verbena, Sweet potato vine and Angelonia.

Wildlife: The clump can shelter small invertebrates, but its wind-pollinated flowers provide little nectar value. The normally sterile 'Rubrum' offers little seed for birds.

• Winter death: frost and cold, wet soil commonly kill plants; grow as an annual or overwinter under bright, frost-free cover.
• Crown or root rot: improve drainage, avoid burying the crown and do not leave pots standing in water.
• Greenish foliage and weak flowering: move to full sun and avoid excessive nitrogen fertiliser.
• Spider mites under cover: inspect for fine webbing and stippled leaves; rinse foliage and use insecticidal soap labelled for the pest if needed.

Not known to be toxic to cats, dogs, horses or people. The leaves and bristly flower heads can cause minor mechanical irritation, and swallowing coarse grass may cause digestive upset.

Where it spreads. 'Rubrum' is generally sterile and is not known for aggressive self-seeding. Do not confuse it with fertile green fountain grass, Cenchrus setaceus, which is invasive in Hawaii, California, Arizona and parts of Australia. Restrictions may depend on the botanical identity and local law; check local rules before buying or moving plants, particularly in Australia.

• Green fountain grass (Cenchrus setaceus)

  Usually has green foliage rather than burgundy leaves and produces viable seed freely; it is the invasive plant in many warm regions.

• Swamp fountain grass (Cenchrus alopecuroides)

  Usually has green leaves and shorter, denser bottlebrush flower heads; it is substantially more cold-hardy.

• Purple-leaved pearl millet (Cenchrus americanus)

  Has much broader leaves, more upright stems and thick, dense flower spikes rather than airy, arching plumes.

The common name describes the purple foliage and fountain-like spray of arching leaves and flower stems.

Propagation. Divide healthy overwintered clumps in spring as growth resumes, keeping roots and growing shoots on each section. 'Rubrum' is normally sterile and must be propagated vegetatively to retain its characteristics.

Accepted botanical name

Cenchrus setaceus

Native range

Afghanistan, Algeria, Chad, Djibouti, Egypt, Eritrea, Ethiopia, Kenya, Lebanon-Syria, Libya, Morocco and Oman.

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