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Cupressaceae FAMILY Least Concern

Juniperus horizontalis

Juniperus horizontalis

Edibility
2/5
Medicinal
2/5

Safety & Hazards

None known

Cultivation Details

HabitEvergreen Shrub
GrowthSlow

Juniperus horizontalis is a very cold-hardy plant, able to tolerate temperatures down to around -30°c when fully dormant[1]. It occurs in areas with continental climates that are typically dry and often experience great annual and diurnal temperature variations[2]. Succeeds in a sunny position in most soils so long as they are well drained, preferring a neutral or slightly alkaline soil[3] and succeeding on chalk[1]. It is often found in the wild on sandy, poorly developed soils, and has a preference for high calcium soils[2]. Succeeds in dry soils[1]. The plant tolerates a pH in the range 4.4 - 8.5[2]. Creeping Juniper is a desirable species for horticulture in cool temperate to cold regions, and has been cultivated since the early 19th century. There are now numerous garden forms (cultivars) known, selected both in Europe and North America and widely used in gardens and parks[4]. Juniperus horizontalis currently holds the record as the smallest conifer in the world, since cone-bearing individuals only 4cm tall have been recorded[5]. An aggregate species[6]. There are many named varieties selected for their ornamental value[1]. 'Bar Harbour' is very salt-resistant[1]. Juniperus horizontalis, a prostrate species, hybridizes with the trees Juniperus virginiana and Juniperus scopulorum, and is closely related to both[7]. A dioecious species, both male and female forms must be grown if seed is required.

Propagation

The seed requires a period of cold stratification. The seed has a hard seedcoat and can be very slow to germinate, requiring a cold period followed by a warm period and then another cold spell, each of 2 - 3 months duration[8, 9]. Soaking the seed for 3 - 6 seconds in boiling water may speed up the germination process[3]. The seed is best sown as soon as it is ripe in a cold frame. Some might germinate in the following spring, though most will take another year. Another possibility is to harvest the seed 'green' (when the embryo has fully formed but before the seedcoat has hardened). The seedlings can be potted up into individual pots when they are large enough to handle. Grow on in pots until large enough, then plant out in early summer. When stored dry, the seed can remain viable for several years[10]. Cuttings of mature wood, 5 - 10cm with a heel, September/early autumn in a cold frame. The cuttings root easily[2]. Plant out in the following autumn[10, 8]. Layering in September/early autumn. Takes 12 months[8]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Juniperus+horizontalis>

Pollinators

Wind

References

  1. [1]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  2. [2]Fire Effects Information System — http://www.feis-crs.org/feis/ ↩︎An on-line information site with comprehensive information on over 1,100 species of plant. Mainly developed to supply information on the effects of fire on plants and animals, it also contains a wealth of other information on the plants
  3. [3]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  4. [4]Mansfeld's Database of Agricultural and Horticultural Plants — http://mansfeld.ipk-gatersleben.de/pls/htmldb_pgrc/f?p=185:3:4292127278597336 ↩︎Terse details of a huge range of useful plants.
  5. [5]The Gymnosperm Database — http://www.conifers.org/index.htm ↩︎A vast amount of information on conifers and families of gymnosperms.
  6. [6]Flora of Canada — Livingstone. B. · National Museums of Canada · 1978 · ISBN 0-660-00025-3 ↩︎In 4 volumes, it does not deal with plant uses but gives descriptions and habitats.
  7. [7]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
  8. [8]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  9. [9]Conifers. — Rushforth. K. · Christopher Helm · 1987 · ISBN 0-7470-2801-X ↩︎Deals with conifers that can be grown outdoors in Britain. Good notes on cultivation and a few bits about plant uses.
  10. [10]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  11. [11]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
  12. [12]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  13. [13]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.