Common juniper: where it grows, price and pruning

Common juniper (Juniperus communis) is a conifer native to the Netherlands that stays green all year. It usually grows as a loose shrub 4 to 8 metres tall. The flowers in April and May are inconspicuous. Female plants bear blue-black berries, which take two years to ripen. Juniper needs an open spot on dry, poor soil.

Common juniper at a glance

Leaf

all year

Flower

April to May

Fruit

all year

JanFebMarAprMayJunJulAugSepOctNovDec

How do I recognise common juniper?

Start with the needles. They grow in whorls of three around the twig. Each needle is short and stiff and ends in a sharp point. A broad whitish band runs along its upper side. The bark is grey-brown to red-brown. On older plants it peels away in long, narrow strips.

A juniper is either male or female, never both. Male plants carry yellow cones of a few millimetres in spring. Round berries of 5 to 9 millimetres grow on a female plant. In their first year the berries are green. In the autumn of the second year they drop in large numbers.

Garden centres also sell other junipers, such as the Chinese juniper (Juniperus chinensis). Besides needles, that species carries tiny scale-like leaves that lie flat against the twig. A wild common juniper has needles only.

Where does common juniper grow best?

Common juniper needs full sun: more than six hours of direct sun a day around midsummer. Dry, poor sandy soil suits it best, but chalky soil works too. In the wild the species grows on heathland and drift sand. There it has declined sharply since 1950.

A juniper slowly dies back in these spots:

• Under or beside tall trees. Juniper copes poorly with shade. Lasting shade is fatal, above all for a young plant.
• On ground where puddles remain after rain. Wet soil turns the needles brown, and the roots can start to rot.

In winter a juniper stays grey-green. A female plant still carries berries then.

So a juniper needs an open spot, away from high walls. In the app your own plot opens to scale, with the buildings around it. That way you can see in advance which corner of the garden lies clear of walls and buildings.

Planting and caring for common juniper

The best time to plant a juniper is late October, early November or March. A plant from a pot can go in at another time too, but not in heat or drought. Nurseries sell the wild species mostly young, in a small pot.

Plant a free-standing juniper 1.25 to 2 metres from the fence or the path. That is half the spread of a full-grown plant. On planting day this looks far too roomy, but the shrub only fills that space after many years. Water regularly for the first two years. Drying out is the main thing that kills a young juniper.

Many birds breed from March through July, a few already in February. If you cut in those months, look between the branches for a nest first.

What can go wrong with common juniper?

The needles turn brown. Drought, frost, wet soil or a cold, drying wind is often the cause. On wet soil, root rot can be to blame as well. Brown patches sometimes fill in again, but that takes years.

There are white specks on the needles. That is juniper scale, a scale insect of juniper and other conifers. A few do no harm: ladybirds and some birds eat them. With many insects the needles turn yellow and twigs die back.

You see no berries. Only a female plant bears berries. The pollen travels on the wind from a male plant, so one has to grow nearby.

Which birds and insects use common juniper?

The common crossbill eats mainly conifer seeds, but juniper berries too. For the greenfinch, a dense juniper is a place to rest and, in spring, to nest. The firecrest also builds its nest in a juniper now and then.

The caterpillar of the juniper carpet (Thera juniperata), a moth, feeds on juniper and other conifers. In gardens this species also lives on cultivated conifers.

Is common juniper poisonous or edible?

Common juniper is mildly poisonous. The sap can irritate the skin, so wear gloves when you prune. In small amounts the ripe blue-black berries are a well-known flavouring, in jenever, gin and sauerkraut. Large amounts of berries can damage the kidneys. The green, unripe berries are very resinous and not edible.