Juniperus communis: planting, pruning & toxicity of common juniper
Juniper berries are famous for their use in gin-making, cooking and as an herbal remedy. In this article we will guide you through all there is to know about planting, caring for and making use of juniper.
Common juniper (Juniperus communis) is not just pretty, but also provides a plentiful supply of food for birds. As long as it gets enough light, it will grow as a tree or shrub almost anywhere and can also be planted to create a beautiful juniper hedge. Here is how to grow your own juniper plant.
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Common juniper: profile
The common juniper plant is known for its blue berries (which are in fact cones) and distinctive growth habit. It is the most widespread of the conifers and is found across the northern hemisphere from North America to Africa. It can grow both as a shrub and as a tree and reaches heights of between 5 and 8 metres. But how quickly does juniper grow? With a growth rate of 10 to 15 centimetres a year, the juniper species is a slow-growing woody plant. The evergreen juniper has prickly, grey-green needles that always grow in whorls of three. On the top of the needle there is a white stripe, called a stomatal band, which is formed by a row of tiny pores in the surface. Common juniper flowers from June onwards with small, inconspicuous flowers in the leaf axils. After fertilisation, the cone fruits typical of junipers, which look like berries, develop from these flowers. However, the flowers and berries are only found on female plants. Since juniper is a dioecious plant, at least two plants (one of each sex) are needed for the formation of fruits. Only once the cones have matured for two to three years and have turned a dark blue colour are the fruits ready to be harvested and used.
By the way: The common juniper is the only species of the Juniper genus that produces edible fruits.
The most beautiful Juniperus communis varieties
Alongside the wild juniper variety, there are some Juniperus communis cultivars that stand out either because of their growth habit or because of their needle colour.
- Juniperus communis ‘Gold Cone’: This juniper variety’s golden yellow needles are very striking. Juniper ‘Gold Cone’ grows as a densely branched, columnar tree and reaches heights of about 3.5 metres.
- Juniperus communis ‘Hibernica’: This cultivar is also known as a columnar juniper, growing with a compact, columnar shape. Juniperus ‘Hibernica’ is particularly suitable as a solitary tree, but also as a Juniperus communis bonsai.
- Juniperus communis ‘Repanda’: This is a low, ground-covering juniper variety. It is also known as creeping juniper.
Planting juniper: where and how
The decorative and low-maintenance juniper can be used in many ways in the garden, whether as a solitary feature tree, as part of a shrub border, for feeding birds or even for harvesting your own crop.
Common juniper prefers a sunny location. The soil should ideally be loose, well-draining and kept dry to moist, never waterlogged. It is best to plant junipers in spring. To loosen compacted or clayey soils, mix in about a third of sand to two thirds of soil when digging the planting hole. Before planting, submerge the root ball of the young juniper in water, then, after it has soaked, place it in the planting hole. Fill in the gaps with the sand and soil mixture, press everything down and water regularly over the next few days.
If you want to create a juniper hedge, plant several shrubs close together. Since juniper needs a lot of light, cut the hedge into the shape of a trapezoid, allowing light to reach the lower branches. Keep a plant spacing of about 50cm between each juniper, although this can vary depending on the variety of juniper you are using. Juniperus communis ‘Golden Cone’, for instance, is a perfect variety for growing a juniper hedge, whereas ground-covering varieties such as Juniperus communis ‘Repanda’ are not well suited.
It is also possible to cultivate a common juniper bonsai. The variety ‘Hibernica’ is ideal for this. It tolerates root pruning well, so can be easily kept as a miniature tree. The location requirements are the same as those for the larger juniper trees or shrubs. For more helpful tips, read our article on how to plant and care for a bonsai.
Common juniper care: pruning, fertilising and watering
Common juniper is relatively easy to care for. After planting, the young trees need a little more attention, but as soon as they are well rooted, the juniper should grow well on its own.
During long, dry periods, water your young juniper plants. Watering is especially important in the time just after planting. Well established plants, on the other hand, do not need watering and can survive drought without any issues. It is only necessary to fertilise your juniper if it is not growing well enough. If the garden soil is particularly poor in nutrients, give your juniper a boost of fertiliser when planting to support healthy growth and apply annually in the spring from then on. Our Plantura All Purpose Plant Food, for example, is ideal for this. It is a slow-release fertiliser made from natural ingredients that is also pet-friendly.
- Perfect for a variety of plants in the garden & on the balcony
- Promotes healthy plant growth & an active soil life
- Long-lasting fertiliser that is free from animal products - child & pet friendly
If you are cultivating your juniper as a bonsai, apply a special bonsai fertiliser during the growing season.
As juniper grows very slowly, it should only be pruned back a little, but regularly. Pruning once a year is plenty. Choose a frost-free day during the growing season, preferably in spring before the juniper plants begin budding. Avoid radical, heavy pruning at all costs, as juniper will not sprout back from the old wood.
Juniperus communis uses
As soon as the juniper berries have turned dark blue, it is time to harvest the fruits. It can take up to three years before the cones ripen in the autumn. You can either collect the fruits with gloves or gather them in a cloth by laying one on the ground underneath the common juniper tree and shaking the branches so that the cones fall onto it. To preserve the juniper berries, you can simply dry the fruits. The sweet yet bitter tasting fruits are used to enhance the flavour of spirits, such as gin, and can also be brewed into tea or used in cooking. Tea made from juniper berries is said to purify the blood and aid digestion. However, you should not consume large quantities of juniper fruits as they do also contain irritants. You can also make use of juniper twigs, for instance to smoke meat with. If you have kidney problems or are pregnant, however, you should refrain from eating juniper berries to avoid any unnecessary risk.
By the way: This beautiful conifer also attracts some feathered visitors to the garden as the juniper cone berries provide a valuable food source for many bird species, such as the song thrush and the fieldfare.
Is common juniper poisonous?
The cone berries of the common juniper should only be consumed in moderation, as excessive consumption can be harmful to the kidneys. This is due to essential oils found in the juniper needles. Juniperus communis is considered toxic in large quantities, albeit only mildly.
The cones of the common juniper also provide lots of food for birds. Find out how you can make your garden more bird-friendly.
