Silver birch: where it grows, planting and what it feeds

Silver birch (Betula pendula) is a tree native to the Netherlands that grows 15 to 20 metres tall. The trunk is white and the thin twigs hang down. In April and May yellow catkins hang from them. The tree wants sun or partial shade and copes with poor sandy soil. In a small garden it gets big.

Silver birch at a glance

Leaf

April to October

Flower

April to May

Fruit

August to September

JanFebMarAprMayJunJulAugSepOctNovDec

How do I identify a silver birch?

Look at the trunk first. On a young tree the bark is red-brown. Later it turns silver-white and peels off. Near the ground, the trunk of an old birch grows dark and rough, as if the bark is splitting open.

Then check the twigs. Young twigs are thin and hang over, and they soon lose their hairs. Tiny resin glands make them feel slightly warty.

A leaf is 3 to 7 centimetres long, diamond-shaped and pointed. Its edge is double-toothed: large teeth with small ones in between. The male catkins hang down and grow 3 to 6 centimetres long. The female catkins stand upright. Each seed has a wing two to three times as wide as the tiny nut.

Watch out for downy birch. Its young twigs grow upwards at an angle, do not hang over and are hairy. The two species also cross with each other, so not every birch is purely one or the other.

Where does silver birch grow best?

Give silver birch sun or partial shade: at least 3 hours of direct sun a day in summer. More sun is fine too. In the wild the tree grows in woodland, on heathland and in the dunes. Acid sandy soil suits it well.

Two places in a Dutch garden cause trouble:

• A narrow back garden. The crown grows 8 to 12 metres wide. In a garden 6 metres wide, the tree hangs far over the neighbours' side.
• Close to the house when someone has hay fever. Birch pollen is a very strong allergen. More than 1 million people in the Netherlands are allergic to it.

In winter the birch stands bare. That is exactly when the white trunk stands out most.

MayJanuaryThe same garden in May and in January. This is a generated image, not a photo.

A drawing of your own plot, to scale, shows how wide your garden really is. Your house and the buildings around it are on it too. That way you choose the spot for the birch before anyone starts digging.

How to plant and look after a silver birch

Plant a bare-root birch, sold without soil around its roots, between November and early March. The tree is dormant then. A young bare-root tree is the cheapest way to buy one, and Dutch nurseries sell it as ruwe berk. A tree in a pot can go into the ground all year round, but autumn or winter is still the best time for it too.

Set the trunk at least 4 to 6 metres from the house, the fence and other trees. That is half the width of the crown. On planting day the gap looks far too wide for such a thin stem. In a lawn, keep a circle around the trunk free of grass.

Water regularly in the first year. Until three years after planting, also water in long dry spells. A birch needs no pruning, and cutting it back hard is a bad idea.

Many birds nest from March through July, and some into August. So check the tree for a nest first.

Silver birch problems and what to do

The leaves have orange spots underneath. That is birch rust, a fungus. In a bad year the leaves drop a little early. A mature tree is hardly bothered by it. Clearing up the fallen leaves in autumn slows the fungus down a little.

Everything under the tree is sticky. Aphids give off a sticky honeydew. Black sooty mould sometimes grows on it. No control is needed, because natural enemies keep the aphids in check. A damp cloth takes the sticky film off tables and chairs.

A thick fungus is growing on the trunk. That may be birch polypore. This fungus grows only on birch and rots the wood. For birches it is the main cause of death. Have a tree with this fungus near the house or a path checked.

The leaves hang limp in summer. The soil is too dry. Birches root shallowly and cope badly with drought. Give the tree a good soaking.

No catkins appear. The tree is still too young. A birch usually starts flowering only at 10 to 15 years old.

Which birds and insects use silver birch?

In autumn and winter the siskin visits, often in small flocks. This little bird hangs acrobatically from the thin twigs. With its pointed beak it picks the seeds out of the birch catkins. The common redpoll also eats mostly birch and alder seed. That winter visitor does not turn up every year, but sometimes large flocks arrive.

The caterpillars of dozens of butterfly and moth species live on birch. The orange underwing is one of them. This small moth flies by day, from late February to late April. The northern winter moth flies later in the year, from October to mid-December.

Is silver birch poisonous?

Silver birch is not known to be poisonous. That does not make it edible. In spring, though, people tap sap from the trunk. They drill shallow holes in the trunk and catch the sap through a small tube. Because the sap contains sugar, it is also fermented into an alcoholic drink.