Alpine clematis

Alpine clematis: how do you recognise it?

Habit

Deciduous climber 2–3 m tall and 1–1.5 m wide, with thin stems that become woody.

Leaves

Compound, with three times three toothed leaflets; fresh green. The leaf stalks twine around supports.

Flowers

Nodding bells 3–5 cm long with four pointed sepals, blue, purple, pink or white, with white ‘petals’ inside; in April–May, sometimes with a small second flush in summer.

Fruit

Silvery-white, silky seedheads from summer into autumn.

Roots

Fine and branched; they like a cool, shaded root run.

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

Why grow it?

• One of the first clematis of the year: it flowers in April, together with the late spring bulbs.
• Also grows on a north wall or in shade, where few other climbers flower.
• Very hardy and not very susceptible to clematis wilt.
• The silvery seedheads decorate the plant from summer into autumn.
• Bumblebees and bees visit the bells in early spring.
• Compact enough for a small garden, a large pot or to grow through a shrub.

Alpine clematis: where does it grow best?

• Sun, partial shade or shade: it flowers anywhere, even on a cold north- or east-facing side.
• Well-drained, humus-rich soil: sand, loam or clay, acid to chalky.
• Moderately moist; keep the roots cool and shaded with a stone, low plants or mulch.
• Provide a trellis, wires or a shrub to grow through: it climbs with its leaf stalks, so it cannot climb a bare wall.
• Plant 1–1.5 m apart, and 30–40 cm from a wall or fence.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

2.5 m tall, 1.5 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Climbing rose: Flowers on the same trellis once the clematis has finished.
• Lenten rose: Flowers at its feet in the same early spring and tolerates shade.
• Lungwort: Blue or pink flowers and spotted leaves for a cool root run.
• Daffodil: Yellow trumpets in April beside the blue bells.
• Ferns: A cool green underplanting in a shady spot.

Alpine clematis: when and how to plant it?

Plant in March–May and September–October.

1. Plant in March–May or September–October, when the soil is neither frozen nor waterlogged.
2. First stand the pot in a bucket of water for a quarter of an hour, until no more air bubbles rise.
3. Dig a hole 40 × 40 cm and mix in compost; on heavy soil put some gravel in the bottom.
4. Set the plant at the same depth as in the pot or at most 5 cm deeper, leaning slightly towards the support.
5. Guide the stems along the cane from the pot to the trellis and tie them in loosely.
6. Water in well and cover the base with mulch or a flat stone to keep the roots cool.

Care

Watering

Regularly in dry weather in the first year; after that during dry spells, especially against a wall where little rain falls.

Feeding

Compost or an organic fertiliser for flowering plants in March.

Mulching

A layer of compost or leaf mould over the cool root run every spring.

Tying in

Guide the young shoots over the trellis in spring; higher up they cling on by themselves.

In a pot

Possible in a large pot of at least 40 cm, with a trellis; water regularly in summer.

Tip: Give it a cool root run and let the stems climb towards the light: a flat stone or low plants over the roots work wonders. Never prune it in winter; at most, trim it lightly after flowering.

Alpine clematis: when to prune it?

Pruning months: May–June.

When: No pruning is needed: it belongs to pruning group 1. To keep it in shape, prune lightly just after flowering, in May–June.

How:

• After flowering, cut over-long or tangled stems back to just above a pair of healthy buds.
• Remove dead and damaged stems.
• Do not prune in winter or early spring: it flowers on last year’s wood, so you would cut off the flower buds.
• An overgrown plant can be cut back hard after flowering; the following year’s display will then be somewhat smaller.

Caution: Wear gloves: the sap can irritate the skin.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In May–June, take internodal cuttings from young shoots and insert them in moist cutting compost under plastic, in a bright spot out of direct sun.

Layering

In spring, lay a low stem in the soil and peg it down; after a year, sever it.

Seed

Sow fresh seed of the species in a pot outdoors in autumn; germination is slow. Varieties do not come true from seed.

Alpine clematis: how does it get through the winter?

Hardy to −30 °C.

• Very hardy, to about −30 °C: it never needs protection in Belgium.
• Leave the seedheads in place; they are attractive in winter too.
• In a pot: stand it against a wall in winter so the root ball does not freeze solid, and keep the compost lightly moist.

Diseases and pests

• Clematis wilt: Stems that suddenly wilt. Rare in this species; cut affected stems back to healthy wood.
• Aphids: On young shoots in spring. Hose them off; ladybirds help.
• Slugs: Eat the young shoots at the base. Pick them off in the evening and keep the base free of debris.
• Powdery mildew: White powder on the leaves in dry summers. Water and keep the plant airy.
• Poor flowering: Usually caused by winter pruning. In future, prune only after flowering.

Through the year

• March: Plant. Compost and mulch over the roots.
• April: Flowering begins. Tie in young shoots.
• May: Flowering. Prune lightly after flowering. Take cuttings.
• June: Finish light pruning. Seedheads appear.
• July: Water in dry weather, especially against a wall.
• August: Water in dry weather. Sometimes a few late flowers.
• September: Plant. Seedheads decorate the plant.
• October: Plant. Sow seed of the species outdoors.
• December: Rest. Do not prune.

Edible and useful

Not edible. All parts of clematis are poisonous: when the plant is damaged it releases protoanemonin, an acrid substance also found in buttercups and anemones. On the skin the sap can cause redness, itching and blisters, especially in people who often prune with bare hands; in the mouth it causes a burning feeling, drooling, vomiting and stomach ache. The acrid, bitter taste puts off most people and animals, but keep small children, dogs, cats, rabbits and guinea pigs away from the plant and the clippings. Horses and other livestock can eat more of it if they reach a clematis over the fence or find the clippings: do not plant it along a field, and never throw the clippings into a field, pen or hutch. Wear gloves when pruning and tying in, and wash your hands afterwards. 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 white ‘petals’ in the centre are really modified stamens; the coloured ‘petals’ are sepals.
• Clematis does not climb with tendrils but with its leaf stalks, which curl around wires and twigs.
• The name Clematis comes from the Greek klēma, a twig or vine shoot.