The joys of juniper
Junipers might have fallen out of fashion, but this varied genus is easy to grow and there’s one to suit every garden… especially if you love gin!
How to grow your own gin: plus take part in the great juniper hunt!
Fancy a homegrown gin and tonic after a day in the garden? In that case you might want to plant a juniper. Specifically a common juniper, since it is the berries of Juniperus communis which are the primary botanical flavouring used in gin (in fact, in some markets the law requires juniper to be the predominant flavour in anything seeking to be classified as gin). Part of the Cypress family, junipers are conifers, the ancient trees or shrubs that reproduce by means of cones, not flowers and fruit. The 50-67 species (taxonomic views differ on this) in the Juniperus genus are native to Europe, Middle East, Asia, India, North America, and South America. They have a wide range of native habitats, some are found in the cold sub-Arctic or mountainous regions while others thrive in warmer areas. Their size and shape are equally varied, ranging from tall trees to low spreading shrubs with over 170 cultivated varieties. All produce the classic needle-like evergreen foliage we associate with conifers, with leaf colours ranging from dark green through to light blue-green and yellow.
It’s the fleshy female seed cones that differentiate junipers from most of their other relatives, particularly those blue “berries” of Juniperus communis (also used as an aromatic spice for flavouring game dishes).
Juniperus communis is the most widespread of the junipers, found mainly in cooler parts of the northern hemisphere but able to grow in a range of habitats. It varies in form from low groundcover shrubs to small trees.
Junipers and other conifers have rather fallen out of fashion with gardeners these days, but the conifer genus has been a passion for nurseryman Denis Hughes since he was given his first one ( Chamaecyparis pisifera ‘Boulevard’), as a wedding present in 1965. He has since grown thousands. “Before the end of that decade I had produced 100,000 plants from that one Chamaecyparis. Most were sent to Japan.” Denis, who owns Blue Mountain Nurseries in Tapanui near Gore, says that he stocked at least 700 different conifers during their peak popularity. “Now we wouldn’t even have 70.” But he insists that these hardy evergreens are a sorely underestimated group of plants, valuable not only for their ability to cope with wind exposure and cold temperatures, but also for their longevity, low maintenance requirements, varied colours and form. Take Juniperus chinensis ‘Kaizuka’, grown as street trees throughout Invercargill. “They couldn’t be in a worse spot as far as exposure goes but you can’t fault their performance,” Denis says. “I think we shouldn’t allow gardening and landscape to be dictated to by fashion. We need to take a much longer term view of it. If you look at some of the beautiful old conifers in parks, their size and form, they really contribute to the landscape. Some of the Juniperus ‘Kaizuka’ I come across are over 50 years old now and they have a seriously good shape to them.” He also rates the groundcover Juniperus communis ‘Depressed Star’. “It has lovely bright green foliage and good horizontal form. It and Juniperus communis ‘ Repanda’ are groundcovers with a lot going for them. Columnar style conifers are still very popular. Small trees like the Noah’s Ark juniper, Juniperus communis ‘Compressa’, are like exclamation points in the landscape. “Diversity of form is a big plus with this genus,” he continues. “From the lowest growing carpet juniper, Juniperus taxifolia ‘Lutchuensis’ to those with a nice upright form like Juniperus chinensis ‘Spartan’. And there’s the weeping Himalayan juniper, Juniperus recurva var. coxii. It’s also called the Chinese coffin juniper because the story goes that the nobility in China would plant one when a new baby was born. The timber from the tree was then used to make the coffin when that person died.”
How juniper is used
Junipers have an extensive range of practical uses. As well as using the berries to make gin and as a spice, the fragrant timber is popular for making furniture and coffins, wood carving and burning to smoke food. Oil of juniper, made by distilling wood and leaves, is used in perfumes and in herbal medicine as a diuretic. Juniper berries are steam distilled to make an essential oil used to treat respiratory infections and skin conditions. Herbalists use extracts of juniper as a health tonic, to treat urinary tract infections and more (but consult a health professional before using yourself as extracts can be extremely powerful).
One of the most interesting uses is juniper ash which is added to corn-based foods eaten by the Navajo people as a traditional source of calcium. One teaspoon of juniper ash is said to contribute the same amount of calcium as one cup of milk.
Growing conditions
Like most conifers, junipers love full sun although they’ll cope with light shade. They are tolerant of drought, salt-laden winds, air pollution and most soil types as long as they are well drained, with a preference for soil with a little acidity. “They do really well in the central North Island, on the central plateau with its volcanic soil,” says Denis. “Places with a high elevation, dry cold and harsh winters. Conifers laugh at those sorts of conditions.”
Don’t plant them too close to other plants or near buildings though. Denis thinks the reason so many conifers planted in the 1970s were later taken out is that they were too close to each other or to houses.
While newly planted junipers need to be watered during summer, wet feet are a big problem for this species – and indeed for most other conifers too.
“When their roots get too wet it encourages phytophthora to develop, as we know from the spread of kauri dieback. You can fix the drainage and add beneficial microorganisms to soil but once the tree is infected it’s generally gone,” Denis advises.
Cypress canker can be a problem too, mostly in humid and warm coastal areas. “The spores are airborne so when you have the right conditions such as wind damage and humidity they can spread quickly. It seriously disfigures the trees and will eventually kill it. You can prune canker out but a power saw is generally the best idea, to reduce pressure on the ones left.”
Junipers should be only pruned occasionally, to keep in shape or in their allocated space, advises Robyn Abernethy, Rock, Water and Alpine Collection Curator at Dunedin Botanic Garden which has about 50 different juniper species and cultivars in its plant collection.
“We shouldn’t allow gardening and landscape to be dictated to by fashion. We need to take a much longer term view of it.”
“Conifers in general should only be pruned lightly and often – not past healthy growth. However, many junipers will respond very well to heavy pruning and even re-sprout from bare wood.”
Juniper propagation
Junipers are dioecious which means that male and female flowers are borne on different plants. You need both to produce seed that can take 2-3 years to ripen. It’s easier to grow junipers from cuttings but this is not always a straightforward process, Denis Hughes points out. “Conifers are slow to propagate, especially when cuttings are taken from old trees. I try to choose young, vigorous specimens but sometimes I have to propagate from older trees to keep the gene pool in the nursery going. It’s not unusual for them to take a year to root whereas cuttings from juveniles can root as quickly as six weeks.”