Juniperus sp.



Juniperus spp.

L. 1753

pronounced: jew-NIP-er-uss species

(Cupressaceae — the cypress family)

common name: juniper

Juniperus is the classical Latin word (iuniperus) for the juniper tree. This is one of the ground-covering species; I am not sure which one, but I suspect it may well be a cultivar of Juniperus horizontalis.

In parts of the garden where a good, tough, weed-suppressing ground cover is needed, the ground-covering junipers take a lot of beating. Junipers vary in size and shape from tall trees 20 – 40 m high, to columnar or low spreading shrubs with long trailing branches. They are evergreen with needle-like and/or scale-like leaves, and can be either monoecious or dioecious. The female seed-cones are very distinctive, with fleshy, fruit-like coalescing scales that fuse together to form a berry-like structure from about 5 to 25 mm long, with 1 – 12 unwinged, hard-shell seeds. In some species these cones are red-brown or orange, but in most they are blue; often they are aromatic and can be used as a spice. The seed maturation time varies between species, from 6 to 18 months after pollination. The male cones are similar to those of other Cupressaceae, with 6 – 20 scales. Most shed their pollen in early spring, but some species pollinate in the autumn. In Juniperus horizontalis, each layer of foliage grows on the top of the layer below, so they become quite dense. This denseness means that very little light reaches the ground, so that weed growth is not encouraged. The needle-leaves of junipers are hard and sharp, especially of juvenile foliage, which makes them prickly to handle.

Although juniper ground-covers can be grown on flat land, they are most prized as plants that will cover a sunny slope, where they serve three purposes: erosion control, weed control, and eliminating the need to mow in places where footing is treacherous. Many other plants find it difficult to thrive in such places, where water runs off so quickly that plants tend to become thirsty; but juniper is quite drought-tolerant, and likes good drainage.

dangerous 2Juniper ‘berries’ are used in both cooking and in making gin; but be careful: the berries of some species can be poisonous, and you should not use juniper berries unless you are absolutely certain as to the species, and have checked that they are edible. The berries are green when young, and do not assume their ripe colour until quite a few months have passed (8 – 2 4 months according to species). Both mature and green berries can be found growing next to each other on the same plant. Juniper berries are used in northern European, and particularly Scandinavian, cuisine to flavour meat dishes, especially wild birds and game meat.

As mentioned earlier, they are also used to give the flavour to gin, a drink developed in the Netherlands in the 17th century. It was first intended as a medication; juniper berries are a diuretic, and were also thought to be an appetite stimulant and a remedy for rheumatism and arthritis. Western American native tribes are also reported to have used the juniper berry as an appetite suppressant in times of famine. The name gin itself is derived from either the French genièvre or the Dutch jenever, both of which mean ‘juniper’. An essential oil extracted from juniper berries is used in aromatherapy and perfumery. The essential oil can be distilled out of berries that have already been used to flavour gin.

Probably the most used Juniper timber is from Juniper occidentalis, the Western Juniper of the USA. It has been used since pioneering times for fence posts and fuel, and has an extremely hard heartwood. Modern methods of drying and preserving the timber have widened its use, and now it finds use for panelling, interior building studs, particleboard, veneer and plywood. The wood tends to be difficult to plane.

The caterpillars of Arachnographa micrastrella feed on Juniper.

Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken in Nelly Bay 2010
Page last updated 24th January 2019