Juniper

A juniper bonsai looks like a little mountain tree, and juniper bonsai care is simpler than it looks once you know one rule. Most beginners end up with a Chinese juniper (Juniperus chinensis) or a Japanese garden juniper (Juniperus procumbens 'Nana'). "Juniper" is not one single tree but a whole genus with many species. Care is very similar across the usual bonsai species. The most important point first: a juniper is an outdoor tree and belongs outside.

The most common mistake: keeping it indoors

In garden centres and furniture stores, junipers often sit between houseplants. That is misleading. Indoors, a juniper lacks light, fresh air and, above all, the cold winter rest it needs every year to recharge. Inside, it slowly gets weaker. The tricky part: a juniper shows problems late. Once it turns brown, it is often too late.

• Outdoors all year, on a balcony, patio or in the garden.
• You can bring it inside for a day or two to enjoy it, but no longer.
• Looking for a windowsill tree? Read our guide to indoor bonsai or look at the Chinese elm.

Position: full sun

Junipers love a bright, sunny spot. The more sun, the denser and healthier the foliage pads. In shade the shoots grow long and thin, and the inside of the tree goes bare.

Good airflow matters too. Dense pads with no air moving through them are paradise for pests such as spider mites.

Winter: cold, but protected

Junipers are frost hardy. Frost is normal for them and even necessary. Some junipers turn purple to brownish in winter. Don't worry: that is their winter colour, and they turn green again in spring.

Only the roots in the pot are more sensitive than roots in the ground, because a pot freezes through quickly. From about −10 °C (14 °F), give it shelter: against a house wall, in a cold frame, or in a cold, bright room such as a garage or shed. Not in your warm living room.

Watering: on the dry side

Junipers hate wet feet. Too much water is the most common reason they die, because the roots rot.

• Water only once the top of the soil is slightly dry.
• Then water thoroughly, until water runs out of the bottom of the pot.
• In summer that may be daily, in winter only rarely.
• Misting the foliage now and then helps, especially on hot days.

How to check whether your tree needs water is explained in watering bonsai.

Feeding

From spring to autumn, feed regularly with bonsai fertiliser, following the pack. Take a break in the peak of summer heat, right after repotting, and when a tree is weak.

Pruning: scissors, not pinching

People used to say you should only pinch junipers with your fingers. Today many growers advise against it: constant pinching weakens the tree, and the torn tips turn brown. Better:

• Cut long shoots that stick out of a pad at their base with sharp scissors, once or twice a year during the growing season.
• Never cut across the foliage like a hedge. Cut needles turn brown and look ugly for a long time.
• Thin out pads that are too dense from below, so light and air can get in.
• Every branch needs green tips. A juniper does not regrow from bare wood. A branch without foliage dies.

Which scissors work best is covered in bonsai tools for beginners.

Needles or scales?

Many junipers have two kinds of foliage. Juvenile foliage is needle-like and prickly. Adult foliage is made of tiny, soft scales. Young plants usually carry needles, scales come later. Hard pruning, heavy bending or too much water can make the tree push out needle-like shoots again. That is not damage, but it tells you: give it a rest.

Wiring and repotting

• Wiring: best in autumn or very early spring. Check the wire regularly so it does not cut into the bark.
• Repotting: about every two years in spring, older trees less often. Use free-draining bonsai soil and only remove a little of the roots.

In Japan

In Japan, the favourite bonsai juniper is called shinpaku (真柏, often written "shimpaku"). It is a mountain form of the Chinese juniper (Juniperus chinensis var. sargentii) that grows wild on high mountain rock faces and on sea cliffs. The character 真 means "true", and 柏 here stands for conifers of the cypress family. Trees from the mountains near Itoigawa in Niigata Prefecture are especially famous and prized for their fine, small foliage.

Together with pines, shinpaku belong to the classic evergreen bonsai, known as "shōhaku" (松柏, pines and junipers). At exhibitions and in bonsai museums, old shinpaku are among the most admired trees.

Shinpaku are known for deadwood: parts of branches or the trunk have died and been bleached white by wind and sun. A dead, white branch is called jin (神), and a dead, white area on the trunk is called shari (舎利). The contrast of white wood, brown bark and green foliage is seen as a symbol of a tree that has stood up to wind and weather for centuries. As a beginner you don't need to create deadwood. It is enough to recognise it and understand why it is so admired.

Toxic to pets?

We could not find reliable information specifically on whether juniper is toxic to cats or dogs. Juniper contains aromatic oils, and the berries in particular can upset the stomach. So be careful and place the tree where pets cannot chew on it.