Dwarf willow

How to recognise it

Growth form

Creeping dwarf shrub 1–5 cm tall, with woody stems that run mostly underground or through moss and root there.

Leaf

Almost round, 0.5–2 cm, with a finely toothed edge and a clear network of veins; glossy green and hairless, usually only two or three leaves per twig.

Flower

Dioecious: there are male and female plants. Small catkins of 0.5–1.5 cm with only a few flowers, at the twig tips, shortly after the snow melts (May–July).

Fruit/seed

Reddish capsules that split open and release tiny seeds with white down, carried off by the wind.

Roots

Creeping woody stems and roots that form a network in the top layer of soil and moss.

Confusion with

Other dwarf willows such as creeping willow are larger and have elongated, often hairy leaves. Net-leaved willow also has round leaves, but they are larger, thicker, greyish-white underneath and deeply veined.

Flowering: May–July · Pruning: March

Why grow it?

• A living piece of the ice age: a tundra and high-mountain plant in miniature.
• A real willow with catkins, but pocket-sized: fun to show to children and plant lovers.
• In the mountains ptarmigan and reindeer eat its buds and leaves; the catkins attract flies and bumblebees.
• A green ground cover for an alpine trough, between stones and moss.
• In autumn the round leaves turn yellow.

Dwarf willow: where does it grow best?

• In the wild: snowbeds, rock ledges, summits and tundra, especially where snow lies late.
• Usually acid, stony soil that stays cool and moist but drains well.
• In the garden: full sun to light shade, in an alpine trough, a rock garden or between large stones, in soil that never dries out.
• In the Belgian lowlands preferably with some afternoon shade: it likes cool feet and a cool head.

Goes well with

• Moss campion: A small pink cushion from the same mountains, for between the stones.
• Purple saxifrage: Early purple flowers on a low mat.
• Mountain avens: A creeping dwarf shrub with white flowers and feathery seed heads.
• Spring gentian: Deep blue stars in spring.

Dwarf willow: when and how to plant it?

1. Buy it from a nursery specialising in alpine plants; never take plants or cuttings home from the mountains.
2. Plant in March–April or in September.
3. Mix ordinary garden soil with a good share of gravel or grit and a little leaf mould; in a trough, provide drainage holes and a drainage layer at the bottom.
4. Plant at the same depth as in the pot and spread a thin layer of gravel around it: this keeps the stems dry and the roots cool.
5. Water with rainwater and keep the soil evenly moist during the first year, especially in hot spells.
6. Allow 20–30 cm between plants; it takes years before they form a small mat.

Care

Water

In summer, water with rainwater during dry spells; the roots must never dry out completely. In winter, on the other hand, too much wet is harmful.

Feeding

Not needed: poor, stony soil keeps it compact and healthy.

Shade

During heatwaves, move a trough into the shade or stretch shade netting over it.

Weeding

Keep moss and weeds short: this tiny willow is easily overgrown.

Gravel layer

Top up the gravel around the plant a little each spring.

Tip: Lay a few flat stones around the plant: the stems creep underneath, and the roots stay cool and moist, just as on a mountain slope.

Pruning and mowing

Pruning months: March.

When: Not needed; at most a little tidying in March.

How:

• In March, cut out dead twigs.
• You can shorten twigs that grow over the edge of the trough and use them as cuttings.
• Do not prune any further: the plant grows very slowly.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

Like most willows it roots easily: in May–June take cuttings a few centimetres long and put them in a moist, sandy cutting mix.

Layers

Creeping stems root by themselves. In spring, cut off a rooted piece and pot it up.

Seed

Willow seed stays viable for only a short time: sow it as soon as it is ripe on moist soil. You need a male and a female plant.

Dwarf willow: how does it get through the winter?

Hardy to −40 °C.

• Deciduous: the leaves turn yellow in autumn and fall; the woody stems overwinter underground or in the moss.
• Extremely hardy: in the mountains and the far north it survives severe frost, usually protected by a thick layer of snow.
• What it dislikes is a wet, mild winter with standing water: make sure drainage is good.

Diseases and pests

• Heat and drought: Brown leaves in a hot summer. Water with rainwater, move the trough into partial shade and use a gravel layer.
• Overgrowing: Moss, grass and more vigorous alpines easily grow over it. Weed regularly and give it enough space.
• Root rot: In standing water the plant dies. Use gritty soil and make sure the trough drains well.
• Rust: Small orange spots on the leaves, as on other willows. Remove affected leaves; usually it does little harm.
• Aphids: Sometimes on the young shoots. Spray them off with water.

Through the year

• March: Cut out dead twigs. Top up the gravel layer.
• April: Plant. The first leaves appear.
• May: Catkins appear. Take cuttings.
• June: Flowering. Water with rainwater in dry spells.
• July: Last catkins and fluffy seed. Move the trough into the shade during heatwaves.
• August: Water in dry spells. Weed.
• September: Plant. Autumn colour begins.
• October: The yellow leaves fall.
• November: Move a trough to a sheltered spot, out of the winter rain.

Did you know?

• It is often called the smallest tree in the world: a woody plant only a few centimetres tall.
• It grows mainly where snow lies late: sometimes it has only a few months a year to come into leaf, flower and set seed.
• Fossil leaves of dwarf willows show that such tundra plants also grew in the Low Countries during the last ice age.