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Juniperus

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Plant Characteristics
Cultivation
Scientific Names

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Read about Juniperus in the Standard Cyclopedia of Horticulture 

Juniperus (ancient Latin name). Pinaceae. Juniper. Ornamental trees and shrubs grown for their foliage and habit.

Evergreen, with the branchlets spreading in all directions: lvs. either all needle-shaped and in 3's, or needle-shaped and scale-like, and usually opposite, often found on the same plant, the needle-shaped lvs. prevailing on younger plants and vigorous branches, the scale-like ones on older plants: fls. dioecious, rarely monoecious; staminate yellow, consisting of numerous anthers united into an ovoid or oblong catkin; pistillate greenish, minutely globular, with several bracts, each or some bearing 1 or 2 ovules; the bracts become fleshy and unite into a berry-like cone, usually wholly inclosing the 1-6, rarely 12, seeds. The fr. ripens either the first year, as in J. virginiana, or the second, as in J. Sabina and most species, or in the third, as in J. communis.—About 40 species distributed throughout the extra-tropical regions of the northern hemisphere, in Amer. south to Mex. and W. India. Juniperus is closely allied to Cupressus, and sometimes hard to distinguish without fr.; but young plants with needle- shaped lvs. can be almost always told apart, since Juniperus has whitish lines or marks on the upper surface of the lvs., while the similar juvenile forms of allied genera have the whitish marks beneath. Most species are very variable, as well in habit as in the shape of the lvs., which renders the determination of an unknown form, at least without fr., a rather difficult task.

The junipers vary greatly in habit from tall pyramidal trees to low prostrate or trailing shrubs, and have small needle-shaped or scale-like foliage, insignificant flowers and small berry-like fruits usually bluish black and often glaucous, less often brown or orange. Many of the species are hardy North, as J. virginiana, J. scopulorum, J. communis, J. rigida, J. Sabina, J. chinensis, J. Pseudo-sabina, J, sphaerica, J. squamata; others are half-hardy, as J. Oxycedrus, J. macrorarpa, J. recurva, J. excelsa, J. occidentalis, while some, as J. procera, J. Lucayana, J. thurifera and the Mexican species, can only be grown South. All are valuable ornamental plants, and the erect-growing species, mostly of pyramidal or columnar habit, are decorative as single specimens on the lawn or if planted in groups. Some varieties form a very narrow column, and are valuable for formal gardens; the columnar form of J. virginiana is a good substitute in the North for the classical cypress. The low prostrate junipers, as J. communis var. montana, J. horizontalis, J. sabina, and J. squamala, are well adapted for covering rocky slopes or sandy banks. The close-grained, fragrant wood is much used for the interior finish of houses and in the manufacture of small articles, also for posts, since it is very durable in the soil; that of J. virginiana and J. Lucayana is in great demand for pencil-making. The fruits and also the young branchlets of some species contain an aromatic oil used in medicine. The fruit of J. drupacea is edible.

The junipers thrive best in sandy and loamy, moderately moist soil, but grow well even in rather dry, rocky and gravelly ground. They prefer sunny, open situations. They are well adapted for hedges and for planting as shelter or windbreaks; also for seaside planting. Propagation is by seeds, which germinate usually the second and sometimes the third year; to hasten their germination, they may be plunged for 3 to 6 seconds in boiling water, but this should be regarded as an experiment and tried only with a portion of seed. They, are also increased by cuttings of nearly ripened wood in fall under glass, either outdoors or in the greenhouse. As a rule, those with needle-shaped leaves root much more easily than those with scale-like leaves, and the latter are therefore mostly increased by side-grafting during the winter in the greenhouse on young potted plants of the typical form or an allied species. The shrubby species, especially J. Sabina, are also propagated by layers.


Index. albo-spicata, 16. albo-variegata,14,16 alpina, 6. argentea, 14. aurea, 6, 14. aureo-variegata,6,14. australis, 18. barbadensis, 18,19. bedfordiana, 18. bermudiana, 19. californica, 10. canadensis, 6. cannartii, 16. Cedrus, 3. chamberlaynii, 16. chinensis, 14. communis, 6. cupressifolia, 20. densa, 7. depressa, 6. douglasii, 21. drupacea, 1. dumosa, 16. elegantissima, 16. excelsa, 12. fargesii, 8. fastigiata, 6, 20. femina, 14. fortunei, 15. glauca, 15, 16. giobosa, 16. hemisphaerica, 6. hibernica, 6. horizontalis, 21. humilis, 20. jackii, 6. japonica, 14. lucayana, 18. macrocarpa, 2. mascula, 14. Montana, 6. nana, 6. neaboriensis, 2. oblonga, 6. oblong-pendula, 6, and suppl. occidentalis, 11. oxycedrus, 4. pendula, 3,6,14,16. pfitseriana, 14. phoenicea, 9. plumose, 16. procera, 13. procumbens, 14,21. prostrata, 21. pyramidalis, 14,16. recurva, 7,8. reevesii, 14. reflexa, 6. repanda, 7. repens, 21. reptans, 16. rigida, 5. sabina, 20. sabinoides, 20 and suppl. schottii, 16. scopulorum, 17. shephardii, 17. sibirica, 6. sinensis, 14. sphaerica, 15. squamata, 8. stricta, 6,12. suecica, 6. tamariscifolia, 20. tripartite, 16. variegate, 12, 20. venusta, 16. virginiana, 16,18.



The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


Template:Alternateuses

Juniperus
Juniperus communis shrubs in The Netherlands
Juniperus communis shrubs
in The Netherlands
Plant Info
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Cupressaceae
Genus: Juniperus
L.

Species
See text

Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the mountains of Central America in the New World.

Cones and leaves of Juniperus communis

Junipers vary in size and shape from tall trees, 20-40 m tall, to columnar or low spreading shrubs with long trailing branches. They are evergreen with either needle-like and/or scale-like leaves. They can be either monoecious or dioecious. The female seed cones are very distinctive, with fleshy, fruit-like coalescing scales which fuse together to form a "berry"-like structure, 4-27 mm long, with 1-12 unwinged, hard-shelled seeds. In some species these "berries" are red-brown or orange but in most they are blue; they are often aromatic (for their use as a spice, see juniper berry). The seed maturation time varies between species from 6-18 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.

Detail of Juniperus chinensis shoots, with juvenile (needle-like) leaves (left), and adult scale leaves and immature male cones (right)

Many junipers (e.g. J. chinensis, J. virginiana) have two types of leaves: seedlings and some twigs of older trees have needle-like leaves 5-25 mm long; and the leaves on mature plants are (mostly) tiny (2-4 mm long), overlapping and scale-like. When juvenile foliage occurs on mature plants, it is most often found on shaded shoots, with adult foliage in full sunlight. Leaves on fast-growing 'whip' shoots are often intermediate between juvenile and adult.

In some species (e.g. J. communis, J. squamata), all the foliage is of the juvenile needle-like type, with no scale leaves. In some of these (e.g. J. communis), the needles are jointed at the base, in others (e.g. J. squamata), the needles merge smoothly with the stem, not jointed.

The needle-leaves of junipers are hard and sharp, making the juvenile foliage very prickly to handle. This can be a valuable identification feature in seedlings, as the otherwise very similar juvenile foliage of cypresses (Cupressus, Chamaecyparis) and other related genera is soft and not prickly.

Juniper is the exclusive food plant of the larvae of some Lepidoptera species including Bucculatrix inusitata and Juniper Carpet and is also eaten by the larvae of other Lepidoptera species such as Chionodes electella, Chionodes viduella, Juniper Pug and Pine Beauty.

Classification

The number of juniper species is disputed, with two recent studies giving very different totals, Farjon (2001) accepting 52 species, and Adams (2004) accepting 67 species. The junipers are divided into several sections, though (particularly among the scale-leaved species) which species belong to which sections is still far from clear, with research still on-going. The section Juniperus is an obvious monophyletic group though.

Juniper needles, magnified. Left, Juniperus communis (Juniperus sect. Juniperus; note needles 'jointed' at base). Right, Juniperus chinensis (Juniperus sect. Sabina; note needles merging smoothly with the stem, not jointed at base).
Juniperus phoenicea on El Hierro, Canary Islands
An Eastern Juniper in October laden with ripe cones.

Cultivation and uses

Juniper berries are a spice used in a wide variety of culinary dishes and best known for the primary flavoring in gin (and responsible for gin's name, which is a shortening of the Dutch word for Juniper: genever). Juniper berries are also used as the primary flavor in the liquor Jenever and sahti-style of beers. Juniper berry sauce is often a popular flavoring choice for quail, pheasant, veal, rabbit and other meat dishes.

Many of the earliest prehistoric people lived in or near juniper forests which furnished them food, fuel, and wood for shelter or utensils. Many species, such as J. chinensis (Chinese Juniper) from eastern Asia, are extensively used in landscaping and horticulture, and as one of the most popular species of bonsai. It is also a symbol of longevity.

Some junipers are susceptible to Gymnosporangium rust disease, and can be a serious problem for those people growing apple trees, the alternate host of the disease.

Some juniper trees are misleadingly given the common name "cedar"-- including the "red cedar" that is used widely in cedar drawers. True cedars are those tree species in the genus Cedrus, family Pinaceae.

References

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  • Adams, R. P. (2004). Junipers of the World: The genus Juniperus. Victoria: Trafford. ISBN 1-4120-4250-X
  • Farjon, A. (2001). World Checklist and Bibliography of Conifers. Kew. ISBN 1-84246-025-0
  • Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4
  • Junipers of the world
  • Gymnosperm Database - Juniperus
  • Arboretum de Villardebelle Photos of cones and foliage of selected species
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