Juniper

Junipers are special kinds of trees and shrubs that belong to the genus Juniperus. They are part of the cypress family and are found all over the Northern Hemisphere. You can find them as far south as tropical Africa, as far north as the Arctic, and in many parts of Asia and Central America.

Depending on how scientists classify them, there are between 50 and 67 different species of junipers. One of the most amazing places to find junipers is in southeastern Tibet and the northern Himalayas, where they grow at very high altitudes—up to 4,900 metres (16,100 feet) above sea level. This makes them one of the highest tree lines on Earth, showing just how tough and adaptable these plants can be.

Description

Junipers come in many sizes and shapes, from tall trees that can grow up to 40 metres (131 feet) high to low, spreading shrubs. They keep their leaves all year and have either needle-like or scale-like leaves. Their seed cones look like small, berry-like fruits and can be blue, red-brown, or orange. These berries are often used as a spice and have a nice smell.

Junipers can bloom and release pollen many times a year in warmer areas. Some junipers have two kinds of leaves: needle-like on young plants and scale-like on older ones. Their leaves can be sharp and prickly, which helps tell them apart from similar plants. Junipers do not have flowers but produce seeds that can stay dormant for a long time until conditions are right for them to grow.

Classification

Junipers are trees and shrubs grouped into a genus called Juniperus. They are found all over the Northern Hemisphere, from tropical Africa to the Arctic, and in parts of Asia and Central America. Some of the highest juniper forests grow in southeastern Tibet and the northern Himalayas, reaching up to 4,900 metres (16,100 ft) above sea level.

The junipers are divided into three main sections based on scientific studies. One section has just one species with large, blue cones. Another has 14 species with blue or red cones, mostly found in the Eastern Hemisphere, one in North America, and one that grows everywhere north. The third section includes about 60 species with different coloured cones, split between the eastern and western hemispheres. Recently, scientists decided these three sections should be separate groups.

Sections

The genus has been divided into sections in somewhat different ways. A system based on molecular phylogenetic data from 2013 and earlier used three sections:

• Section Caryocedrus – 1 species with large, blue, woody, 3-seeded cones; native to the Mediterranean
• Section Juniperus – 14 species with blue or red seed cones, often with 3 seeds; 12 species native to the Eastern Hemisphere, one endemic to North America, and one species, J. communis, circumboreal
• Section Sabina – about 60 species with variously coloured seed cones with 1 to 13 seeds; species about equally divided between the eastern and western hemispheres Juniperus sect. Sabina was further divided into clades.

A new classification of gymnosperms published in 2022 recognised the sections as three separate genera: Arceuthos for section Caryocedrus, Sabina for section Sabina, and Juniperus sensu stricto for section Juniperus.

Species

Juniperus sect. Caryocedrus

Cones with three seeds fused together; needles with two stomatal bands. One species:

• Juniperus drupacea – Syrian juniper

Juniperus sect. Juniperus

Needle-leaf junipers; the adult leaves are needle-like, in whorls of three, and jointed at the base. Species:^{[citation needed]}

• Juniperus sect. Juniperus subsect. Juniperus – cones with three separate seeds; needles with one stomatal band
  • Juniperus communis – common juniper
    • Juniperus communis subsp. alpina – alpine juniper
  • Juniperus conferta, syn. Juniperus rigida var. conferta (Parl.) Patschke – shore juniper
  • Juniperus rigida – Temple juniper or needle juniper
• Juniperus sect. Juniperus subsect. Oxycedrus – cones with three separate seeds; needles with two stomatal bands
  • Juniperus brevifolia – Azores juniper
  • Juniperus cedrus – Canary Islands juniper
  • Juniperus formosana – Chinese prickly juniper
  • Juniperus lutchuensis, syn. Juniperus taxifolia var. lutchuensis (Koidz.) Satake – Ryukyu juniper
  • Juniperus oxycedrus – Western prickly juniper, cade juniper
  • Juniperus macrocarpa – large-berry juniper

Juniperus sect. Sabina

Scale-leaf junipers; adult leaves are mostly scale-like, similar to those of Cupressus species, in opposite pairs or whorls of three, and the juvenile needle-like leaves are not jointed at the base (including in the few that have only needle-like leaves; see below right).

Old World species

• Juniperus chinensis – Chinese juniper
• Juniperus convallium – Mekong juniper
• Juniperus excelsa – Greek juniper
• Juniperus foetidissima – stinking juniper
• Juniperus indica – Himalayan black juniper
• Juniperus komarovii – Komarov's juniper
• Juniperus phoenicea – Phoenicean juniper
• Juniperus pingii – Ping juniper
• Juniperus procera – East African juniper
• Juniperus procumbens – Ibuki juniper
• Juniperus pseudosabina – Xinjiang juniper
• Juniperus recurva – Himalayan juniper
• Juniperus sabina – Savin juniper
• Juniperus saltuaria – Sichuan juniper
• Juniperus semiglobosa – Himalayan pencil juniper
• Juniperus seravschanica – Pashtun juniper
• Juniperus squamata – flaky juniper
• Juniperus thurifera – Spanish juniper
• Juniperus tibetica – Tibetan juniper

New World species

• Juniperus angosturana – Mexican one-seed juniper
• Juniperus ashei – Ashe juniper
• Juniperus arizonica – redberry juniper, roseberry juniper
• Juniperus barbadensis – West Indies juniper
• Juniperus bermudiana – Bermuda juniper
• Juniperus blancoi – Blanco's juniper
• Juniperus californica – California juniper
• Juniperus coahuilensis – Coahuila juniper
• Juniperus comitana – Comitán juniper
• Juniperus deppeana – alligator juniper
• Juniperus durangensis – Durango juniper
• Juniperus flaccida – Mexican weeping juniper
• Juniperus gamboana – Gamboa juniper
• Juniperus grandis – Sierra juniper
• Juniperus horizontalis – creeping juniper
• Juniperus jaliscana – Jalisco juniper
• Juniperus maritima, syn. Juniperus scopulorum – seaside juniper
• Juniperus monosperma – one-seed juniper
• Juniperus monticola – mountain juniper
• Juniperus occidentalis – western juniper
• Juniperus osteosperma – Utah juniper
• Juniperus pinchotii – Pinchot juniper
• Juniperus saltillensis – Saltillo juniper
• Juniperus scopulorum – Rocky Mountain juniper
• Juniperus standleyi – Standley's juniper
• Juniperus virginiana – eastern juniper, eastern redcedar
  • Juniperus virginiana subsp. silicicola – Southern juniper
• Juniperus zanonii (proposed)

Additional species

As of April 2022^[update], Plants of the World Online accepts the following additional species to those listed above:

• Juniperus canariensis Guyot & Mathou
• Juniperus coxii A.B.Jacks.
• Juniperus deltoides R.P.Adams
• Juniperus gracilior Pilg.
• Juniperus mairei Lemée & H.Lév.
• Juniperus morrisonicola Hayata
• Juniperus mucronata R.P.Adams
• Juniperus navicularis Gand.
• Juniperus poblana (Martínez) R.P.Adams
• Juniperus polycarpos K.Koch
• Juniperus przewalskii Kom.
• Juniperus saxicola Britton & P.Wilson
• Juniperus taxifolia Hook. & Arn.
• Juniperus tsukusiensis Masam.
• Juniperus turbinata Guss.

Ecology

Junipers can grow in many different places. In the Lahaul valley, they grow in dry, rocky areas with stony soil. People and animals are using these plants so much that they are disappearing. Western junipers grow in open woodlands where they can get more rain. Without enough fires or animals eating them, these junipers grow too much and change the environment. This makes it hard for other plants and animals to live there.

Some junipers can get a disease that hurts apple trees. They are also the only food for some caterpillars, including types of moths and butterflies.

Cultivation

Junipers are very popular trees and shrubs used in parks and gardens. People have carefully bred them for many years to create many different shapes, colors, and sizes, including very small ones. They are also used in the art of bonsai. Some common types grown include:

• Juniperus chinensis
• Juniperus communis
• Juniperus horizontalis
• Juniperus × pfitzeriana
• Juniperus procumbens
• Juniperus rigida
• Juniperus scopulorum
• Juniperus squamata

Toxicity

In dry places, juniper pollen can float in the air and be breathed into the lungs. This pollen can also irritate the skin and cause a rash. Many people who are allergic to cypress trees can also react to juniper pollen.

Some juniper plants are more likely to cause allergies than others. Plants that produce both male and female parts have a high allergy rating. Plants that are only male also have a high allergy rating because they release lots of pollen. Plants that are only female have a very low allergy rating because they do not produce pollen.

Uses

Juniper wood is flexible and strong for its weight, making it ideal for building hunting bows in some Native American cultures of the Great Basin. Ancient Mesopotamians used juniper oil to protect against harm, and juniper has been used in traditional medicines, such as by the Dineh (Navajo) people for diabetes. In Scotland, juniper smoke is used in special New Year rites to bless homes.

Juniper berries are a popular spice, especially in gin, and are used to flavor many dishes like quail, pheasant, and venison. They can also be made into a tea or used in Finnish beer called sahti. Juniper wood is dense and rot-resistant, often used for fence posts and firewood, and sometimes called "cedar" in specialty uses. The berries can be distilled to make an essential oil with various natural compounds.