Wallis fescue

Wallis fescue: how do you recognise it?

Habit

Small, dense, evergreen tuft about 20 cm tall and wide.

Foliage

Hair-fine and stiff, grey-green to silvery blue (especially the cultivar ‘Glaucantha’).

Flower

Fine, narrow spikes in May–June above the tuft; greenish to silvery, later straw-coloured.

Roots

Dense, fibrous root system that tolerates drought but not wet feet.

Use

Rock garden, gravel garden, green roofs, dry edges and containers.

Flowering: May–June · Plants: March–May and September–October

Why grow it?

• Silvery blue, evergreen tufts that give colour all year round.
• Drought tolerant and very hardy, down to about −25 °C.
• Stays low (about 20 cm): ideal for rock gardens, gravel, green roofs and edges.
• Very little maintenance: no pruning and no feeding needed.
• Attractive in groups as a ground cover or as a low edging along stones and paths.

Wallis fescue: where does it grow best?

• Full sun: in shade it loses its blue colour and the tuft becomes loose.
• Poor, very free-draining soil: sand or loam, neutral to chalky. No wet or rich, heavy soil.
• Dry: very drought tolerant. Wet winters are the danger.
• Plant 20–30 cm apart, about 10–16 plants per m², in gravel or on a dry slope.
• Also suits shallow spots such as a roof or a stone trough.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry

Size

0.2 m tall, 0.2 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Stonecrop: Fleshy leaves and late flowers, with the same need for sun and dry soil.
• Houseleek: Stony rosettes next to the blue needles.
• Thyme: An aromatic carpet in the same dry, sunny spot.
• Rock rose: Colourful flowers in May–June above the low tufts.

Wallis fescue: when and how to plant it?

Plant in March–May and September–October.

1. Plant in March–May or in September–October, when the soil is not frozen.
2. Loosen heavy soil and mix in coarse sand or fine grit. Poor soil does not need improving.
3. Set the plant at the same depth as in its pot, with the crown at soil level.
4. Plant 20–30 cm apart, in small groups or rows.
5. Water in well after planting and then only in prolonged drought during the first season.
6. Lay a thin layer of grit or chippings around the plants; no organic mulch.

Care

Water

In the first season during prolonged drought. After that not needed, except in a pot or trough.

Feeding

Not needed: poor soil keeps the tuft compact and blue.

Weeding

Keep the planting area free of weeds; they grow quickly between small tufts.

Combing

In spring, pull the dead leaves out of the tuft with your fingers or gloves.

Dividing

A tuft that goes bare in the middle is divided every 2–3 years in spring.

Tip: Plant it in full sun on poor, free-draining soil and lay a layer of grit around the tufts: they stay compact and silvery blue. Do not add compost.

Wallis fescue: when to prune it?

When: Do not prune. Just pull the dead leaves out of the tuft in March–April.

How:

• Comb through the tuft with your fingers or a hand rake: the dead leaves come loose.
• Cut off the spent flower spikes in July or leave them as a straw-coloured accent.
• Do not cut the tuft itself short: it recovers poorly.

Caution: Do not cut it hard back: an evergreen tuft recovers poorly from this.

Pruning calendar and basic rules

Propagation

Division

In March–April or September: lift the tuft, divide it into 2–4 pieces with roots and replant them straight away. Do this every 2–3 years.

Seed

In spring on seed compost at 15–20 °C, barely covering the seeds. Cultivars such as ‘Glaucantha’ do not always come as blue from seed: choose division.

Wallis fescue: how does it get through the winter?

Hardy to −25 °C.

• Very hardy down to about −25 °C: no protection needed in Flanders.
• The danger is damp: ensure good drainage and leave the foliage standing.
• In a pot or trough: raise it on feet so water can drain away and place it sheltered against a wall.

Diseases and pests

• Bare centre: A tuft dies out in the middle after a few years. Divide it in spring.
• Winter wet: Brown or rotting tuft in spring because the soil is too wet. Improve drainage with grit and plant on a slight mound.
• Weeds: Grass and weeds grow between the tufts and smother them. Weed regularly and use a layer of grit.
• Loss of blue colour: The blue fades in shade or rich soil. Give full sun and do not feed.

Through the year

• March: Pull dead leaves out of the tuft. Plant or divide.
• April: Plant or divide. First new shoots.
• May: Plant. Flowering begins.
• June: Flowering. Little or no water needed.
• July: Cut off spent spikes or leave them.
• August: Weed.
• September: Plant or divide.
• October: Plant. The foliage stays blue.
• November: Make sure drainage is good.

Did you know?

• The species name valesiaca refers to the Valais, a dry Swiss valley with steppe-like slopes.
• The leaves are so narrow and rolled that they lose little water: an adaptation to dry sites.
• Fescues (Festuca) are also widely used in grass mixes for lawns and green roofs.