Rosemary grevillea

Rosemary grevillea: how do you recognise it?

Habit

Dense, rounded to spreading shrub 1–2 m tall and wide, branched right down to the ground.

Leaves

Needle-like, 1.5–3 cm long, dark green, with a sharp tip and hairy beneath; evergreen.

Flower

Clusters of spider-like flowers in red to pink, with long curved styles; from March to June.

Fruit

Small, hard, leathery follicles containing one or two seeds.

Roots

Fine, shallow roots with so-called proteoid roots that take up nutrients from poor soil; very sensitive to phosphorus.

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

Why grow it?

• An evergreen, finely textured shrub that gives interest all year.
• Red, spider-like flowers in spring and summer, when few other shrubs flower.
• The flowers are rich in nectar and visited by bees.
• Drought tolerant once established and undemanding.
• Lovely in a sunny, acid gravel or heather garden, as a hedge or in a large pot on the terrace.

Rosemary grevillea: where does it grow best?

• Full sun in a warm, sheltered spot, preferably against a south-facing wall.
• Acid (pH 5–6.5), well-drained sandy or loamy soil that is low in phosphorus; not suited to chalky soil.
• Dry to normal moisture: water in the first years, after that it manages in dry spells; avoid wet feet, especially in winter.
• Sheltered from cold east winds; also suitable for a large pot on a sunny terrace.
• Allow 1.2–1.5 m per plant.

Light

Sun

Soil type

Sand or loam

Acidity

Acid

Moisture

Dry or normal

Size

1.5 m tall, 1.5 m wide

Hardiness

Half hardy (to -10 °C): protect it in harsh winters

Goes well with

• Heather: The same acid, poor soil; pink and purple beneath the red flowers.
• Bell heather: A small heath shrub that shares the same position.
• Rock rose: A low bloomer that appreciates the same dry, sunny spot.
• Sheep’s fescue: Fine blue-green grass that frames the shrub lightly.

Rosemary grevillea: when and how to plant it?

Plant in April–May.

1. Plant in April or May, when the soil has warmed up and hard frosts are over, so the plant can root before winter.
2. Dig a hole as deep as the pot and twice as wide; mix the soil with sand for better drainage.
3. Take the root ball carefully out of the pot and disturb the roots as little as possible: they are sensitive.
4. Set the plant at the same depth as in its pot and firm the soil; space 1.2–1.5 m apart.
5. Water well after planting with rainwater, then regularly in dry weather during the first year.
6. Spread a 5 cm layer of bark or pine bark around the base, keeping it clear of the stem.

Care

Watering

Regularly in the first year, after that only in long dry spells. Preferably use rainwater: hard tap water contains lime.

Feeding

Usually not needed. If you do feed, use a special low-phosphorus fertiliser and never an ordinary garden feed or a compost rich in phosphorus.

Mulching

A layer of bark or pine bark in spring keeps the soil cool and acid.

In a pot

Use acid, free-draining compost mixed with sand or perlite; repot every two to three years and preferably water with rainwater.

Spent flowers

Leave them or trim lightly; not necessary.

Tip: Needle-like leaves and red spider flowers in spring. Plant it in a sheltered spot in acid, well-drained soil and never give it a phosphorus-rich feed.

Rosemary grevillea: when to prune it?

Pruning months: June.

When: Straight after flowering, in June. It needs little pruning.

How:

• Lightly shorten faded branches, by about a third, to keep the shrub dense.
• Remove dead or frost-damaged branches back to healthy wood.
• Cut only into leafy wood; do not cut into bare, old wood.

Caution: Do not cut into bare wood: the shrub usually does not shoot again from it.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

In August–September: take 8–10 cm cuttings of semi-ripe wood and insert them in sandy, acid compost under plastic, in a bright, cool spot. Rooting takes several months.

Seed

The seed from the follicles germinates unevenly and gives plants that are not always identical to the parent. Sow in spring in sandy, acid soil.

Rosemary grevillea: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Hardy to about −10 °C in a sheltered spot; in harder frost or cold east wind it can be damaged.
• Cover it with horticultural fleece when it drops below −5 °C and spread a layer of bark around the base in November.
• In a pot: put it in a cool, bright, frost-free room (5–10 °C) and water sparingly.

Diseases and pests

• Yellow leaves (chlorosis): Leaves turn yellow with green veins in chalky soil or with hard water. Use rainwater and acid compost.
• Root rot: The plant wilts and the leaves discolour in wet soil. Provide a free-draining spot and avoid overwatering.
• Phosphorus damage: Brown leaf edges and wilting shoots after feeding with ordinary fertiliser. Stop feeding and water generously.
• Frost damage: Brown, withered leaves after hard frost. Cut back to healthy wood in spring; the plant often recovers.

Through the year

• March: Flowering begins. Remove protective fleece.
• April: Plant or move. Check the soil is acid.
• May: Plant. Mulch. Water in dry weather.
• June: Flowering ends. Prune lightly after flowering.
• July: Water in dry weather, especially pots.
• August: Take semi-ripe cuttings.
• September: Look after cuttings. Prepare potted plants for indoors.
• October: Bring pots inside before the first frost.
• November: Top up mulch. Cover vulnerable plants.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The genus Grevillea is named after Charles Francis Greville (1749–1809), one of the founders of the Royal Horticultural Society.
• Grevilleas belong to the Proteaceae and have special ‘proteoid’ roots that help them grow on very poor, low-phosphorus soil.
• The name rosmarinifolia means ‘with rosemary leaves’, after its needle-like foliage.