Oriental fountain grass

Oriental fountain grass: how do you recognise it?

Habit

Dense, arching clump about 50 cm tall and wide. It grows in a tuft and does not spread by runners.

Foliage

Narrow, grey-green and arching. Straw-coloured in autumn and winter.

Flower

Soft pink to greyish pink, fuzzy, cylindrical spikes of about 10–15 cm, from June to September.

Roots

Fibrous root system that dislikes wet feet. Move or divide it in spring.

Flowering: June–September · Plants: April–May · Pruning: March

Why grow it?

• Months of flowering: soft pink, fuzzy spikes from June to September.
• Compact clump, ideal for the front of a border, a gravel garden or a pot.
• Drought tolerant and low maintenance.
• The soft spikes sway in the wind and look wonderful backlit.
• The straw-coloured clump stays attractive in autumn and winter and protects the crown.

Oriental fountain grass: where does it grow best?

• Full sun: in shade it hardly flowers and the clump flops open.
• Free-draining soil, preferably poor to ordinary: sand or loam, neutral to chalky. No wet, heavy clay.
• Dry to normal: very drought tolerant once established. Standing water in winter is the biggest danger.
• A warm, sheltered spot, for example against a wall or in a gravel bed, improves hardiness.
• Plant 40–50 cm apart.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

0.5 m tall, 0.5 m wide

Hardiness

Half hardy (to -12 °C): protect it in harsh winters

Goes well with

• Woodland sage: Purple flower spikes contrast with the soft pink spikes.
• Ice plant: Flowers pink in August–September and likes the same dry, sunny spot.
• Lavender: Blue-purple flowers and grey leaves on free-draining soil.
• Coneflower: Pink and purple flowers in the same summer period.

Oriental fountain grass: when and how to plant it?

Plant in April–May.

1. Plant in April–May, when the soil has warmed up: it then roots before winter.
2. Dig a hole twice as wide as the rootball. Mix heavy soil with coarse sand or fine grit for better drainage.
3. Set the plant at the same depth as in its pot, with the crown at soil level.
4. Plant singly or in groups of three or five, 40–50 cm apart.
5. Water in well and then in dry weather during the first season.
6. In a pot: use a free-draining compost and a pot with drainage holes.

Care

Water

In the first year, water weekly in dry weather. After that it is drought tolerant; in a pot, water regularly.

Feeding

Little or none: a bit of compost in spring is enough. Soil that is too rich gives floppy clumps.

Mulching

A thin layer of grit or sand around the clump keeps the crown dry. No damp mulch against the crown.

Maintenance

Leave the foliage and spikes standing in winter and cut them back in March.

Dividing

Divide an old clump every 3–4 years in spring to keep it vigorous.

Tip: Plant it in a warm, dry spot and cut it back only in March: the old leaves protect the crown in winter. On heavy soil, mix grit into the planting hole.

Oriental fountain grass: when to prune it?

Pruning months: March.

When: In March or early April, just before the new shoots appear.

How:

• First tie the clump loosely with string: this makes the clear-up easy.
• Cut the clump back to 5–10 cm above the ground with sharp shears or a hedge trimmer.
• Wear gloves: the leaf edges can be sharp.
• Compost the clippings.

Caution: Do not cut back in autumn: the old leaves protect the crown from damp and frost.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In April–May, when new shoots appear: lift the clump, divide it with a sharp spade or knife into pieces with roots and replant them straight away. Do this every 3–4 years.

Seed

In March–April indoors at 18–20 °C on seed compost; barely cover the seeds. Prick out the seedlings and plant them out after mid-May. Cultivars do not always come true from seed.

Oriental fountain grass: how does it get through the winter?

Hardy to −12 °C: protect in harsh winters.

• Moderately hardy: down to about −12 °C. Wet winters are the main danger.
• Leave the foliage standing and tie it loosely in frost: this keeps the crown dry. A layer of dry leaves or straw around the base helps.
• In a pot: stand it against a sheltered wall on pot feet and wrap the pot, or move it to a cool, bright, frost-free place.

Diseases and pests

• Winter wet: Rotting crown or a brown, limp clump in spring. Ensure free-draining soil, plant on a slight slope and leave the foliage standing in winter.
• Rust: Orange to brown pustules on the leaves in a damp summer. Cut off affected leaves, keep the clump airy and do not water overhead.
• Poor flowering: Usually too little sun or soil that is too rich. Move it to a sunny spot and do not feed.
• Floppy clump: Falls open in shade or with too much fertiliser. Give full sun and less feed.

Through the year

• March: Cut the clump back to 5–10 cm. Give a little compost.
• April: Plant. Divide old clumps.
• May: Plant. Water in dry weather. After mid-May, plant out seedlings.
• June: Flowering begins. Needs little water.
• July: Full flower. Water plants in pots.
• August: Flowering.
• September: Flowering ends. Leave the spikes standing.
• October: Leaves turn straw-coloured. Do not cut back.
• November: Protect from winter wet. Shelter pots.
• December: Dormant. Leave the clump standing.

Did you know?

• The name Pennisetum comes from the Latin penna (feather) and seta (bristle), after the bristles on the flower spike.
• The genus Pennisetum has been merged into Cenchrus; that is why this grass is now called Cenchrus orientalis, although the old name is still very common.
• The fountain-shaped clump gives the group its English name ‘fountain grass’.