Hairy alpenrose

Hairy alpenrose: how do you recognise it?

Habit

Low, dense, evergreen shrub about 0.8 m tall and 1 m wide; slow growing.

Foliage

Small, 1.5–3.5 cm, pale green, with an edge of stiff hairs; the young shoots are hairy too.

Flower

Small funnel-shaped flowers in clusters at the shoot tips, pink (sometimes white), in June–July.

Fruit

Small capsules that split open in autumn; the seed is as fine as dust.

Roots

Shallow and fibrous. They dry out quickly and like cool, humus-rich soil.

Flowering: June–July · Plants: March–April and September–October

Why grow it?

• One of the few rhododendrons for neutral to chalky soil, where other mountain rhododendrons fail.
• A compact, evergreen shrub that stays attractive in winter too.
• Flowers in June–July with pink clusters, when most rhododendrons have finished.
• Fully hardy, to about −30 °C.
• Suits a rock garden or cool border; the flowers are visited by bees and bumblebees.

Hairy alpenrose: where does it grow best?

• Half shade to sun, as long as the soil stays cool and moist. Avoid hot afternoon sun.
• Neutral to chalky, humus-rich soil: sand, loam or clay, well drained. It does not need acid soil.
• Evenly moist to wet, with no standing water. It does not tolerate prolonged drought or heat.
• A place between stones in a rock garden is ideal. Allow 80–100 cm per plant.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Normal or wet

Size

0.8 m tall, 1 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Mountain avens: A lime-loving alpine plant with white flowers and fluffy seedheads.
• Saxifrage: Cushions of fine foliage and small flowers between stones.
• Auricula: An alpine primula for the same cool, chalky spot.
• Mountain pine: A small conifer for a mountain feel.

Hairy alpenrose: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Dig a wide but shallow hole and mix the soil with leaf compost for extra humus. On heavy clay, work in some coarse sand or fine grit for drainage.
3. Soak the root ball in a bucket of water until no more air bubbles rise, then gently tease out the roots.
4. Set the plant at the same depth as in its pot, preferably slightly higher, and firm the soil. Water straight away.
5. Spread a 5 cm layer of leaf compost or fine gravel around the base; flat stones between the plants keep the roots cool.

Care

Water

Never let it dry out completely, especially in the first two years and in a pot. Tap water is no problem for this species.

Feeding

Little: some compost or a light dose of organic fertiliser in April. In nature it grows on poor soil.

Mulching

Renew the leaf compost or fine gravel every spring; it keeps the roots cool and moist.

Spent flowers

Not essential. You can snap off the spent clusters by hand to limit seed formation.

Soil

Do not dig or hoe around the plant: the roots lie just below the surface.

Tip: Plant it between limestone rocks in a cool corner and spread a thick layer of leaf compost or gravel around the base: the soil stays cool, moist and well drained.

Hairy alpenrose: when to prune it?

When: It is hardly pruned. Cut off dead twigs in March and remove spent clusters in July–August.

How:

• Snap or cut off spent clusters without damaging the young shoots below.
• In spring, cut dead or frosted twigs back to healthy wood.
• Do not clip it into shape: keep the natural, rounded habit.

Caution: It grows slowly, so prune as little as possible.

Pruning calendar and basic rules

Propagation

Layering

In spring, bend a low, flexible branch down, peg it into humus-rich soil and put a small stone on top. Separate it with its roots after one or two years.

Seed

Scatter the dust-fine seed in January–March on moist seed compost without covering it, and keep it light and cool. Seedlings grow slowly and flower only after many years.

Semi-ripe cuttings

In July–September: take 5–8 cm cuttings of this year’s shoots, remove the lower leaves and insert in a mix of seed compost and sand under plastic. They root slowly.

Hairy alpenrose: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C. In the mountains a thick blanket of snow protects it from hard frost.
• Evergreen leaves can scorch in bright winter sun and dry wind when the ground is frozen: put it in half shade or shelter it, and water on frost-free days.
• In a pot: stand the pot against a wall and wrap it in hessian so the roots do not freeze.

Diseases and pests

• Heat and drought damage: Brown leaf edges and curling leaves in summer. Move it somewhere cooler or shadier, water and apply a thick mulch.
• Vine weevil: Half-moon notches in the leaf edges in summer; the grubs eat the roots. Apply nematodes in August–September to warm, moist soil.
• Root rot: Limp, wilting leaves while the soil is wet. Improve drainage with coarse sand or plant on a slight mound.
• Powdery mildew: A white, powdery coating on the leaves in warm, close weather. Allow space and air, water at the base and remove affected parts.

Through the year

• March: Plant. Cut off dead twigs. Top up the mulch.
• April: Plant. Give a little compost.
• May: Water in dry weather.
• June: Flowering begins.
• July: Flowering. In hot weather water and keep cool.
• August: Remove spent clusters. Apply nematodes against vine weevil grubs.
• September: Plant. Take cuttings.
• October: Plant. Top up the mulch.
• December: Rest. In frost and dry weather, water on frost-free days.

Edible and useful

Not edible. Rhododendrons and azaleas are poisonous in all their parts, including the flowers and nectar: they contain grayanotoxins, which cause drooling, vomiting, weakness, a slow heartbeat and low blood pressure. Goats, sheep and alpacas above all, but also horses, cattle, rabbits and guinea pigs become seriously ill from them, sometimes after only a small quantity of leaves; dogs and cats are at risk too. So never throw clippings over the fence of a field or into a pen or hutch, do not give them to animals, and do not pick greens for rabbits among the shrubs; if in doubt, call your vet at once. In children who put a leaf or flower in their mouth or suck nectar from the flowers, as they do with dead-nettle, it usually goes no further than a burning mouth and nausea, but teach them not to do it. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The species name hirsutum means ‘hairy’ and refers to the hairs on the leaf edge and the young shoots.
• Where it grows alongside the rusty-leaved alpenrose, which prefers acid soil, natural hybrids sometimes occur.
• Unlike most rhododendrons, it grows in the Alps on limestone, often in a thin layer of humus between the rocks.