Common juniper, genévrier commun [French] (Adams 1993), Siberian juniper, dwarf juniper, enebro común [Spanish].
Many infraspecific taxa have been described in this highly polymorphic species, but most are sympatric, or merge into each other where they meet. Thus, the observed morphological differences are for the most part explainable on the basis of habitat differences, chiefly climate. This treatment follows Farjon (2005) in recognizing five varieties, but he cautions that further study is needed, and that variation within populations is comparable to the differences described between the varieties. The varieties are as follows:
"Juniperus communis is the most widespread juniper species, and many subspecies and varieties have been described. A major study, including chemical characters, is needed to clarify the taxonomy" (Adams 1993).
"Shrubs or small trees dioecious, to 4 m (if trees, to 10 m), multistemmed, decumbent or rarely upright; crown generally depressed. Bark brown, fibrous, exfoliating in thin strips, that of small branchlets (5-10 mm diam.) smooth, that of larger branchlets exfoliating in strips and plates. Branches spreading or ascending; branchlets erect, terete. Leaves green but sometimes appearing silver when glaucous, spreading, abaxial glands very elongate; adaxial surface with glaucous stomatal band; apex acute to obtuse, mucronate. Seed cones maturing in 2 years, of 2 distinct sizes, with straight peduncles, globose to ovoid, 6-13 mm, bluish black, glaucous, resinous to obscurely woody, with 2-3 seeds. Seeds 4-5 mm. 2n = 22" (Adams 1993).
This is the most widespread conifer in the world, native to temperate Eurasia, and North America N of Mexico, occupying an extraordinary range of habitats (Farjon 2005). Among other places, it is native to Croatia; Sweden; and the United States. See also Thompson et al. 1999. Hardy to Zone 3 (cold hardiness limit between -39.9°C and -34.4°C) (Bannister and Neuner 2001, variety not specified).
Salomonson [no date, pre-2000] reported that the largest tree "is found at Råå in the province of Närke. It has a girth of 2,8 m. at breast-height." Due to the age and lack of detail in that record, it must be treated as doubtful at this time. A 2016 measurement of a tree at Albero del Poeta, Italy, found a girth of 2.6 m (Monumental Trees 2017), and this is the largest current reliable record. The Monumental Trees database also reports trees of 1.2 to 1.5 m girth growing in Latvia, Poland, and the Netherlands, with measurements from 2013 to 2015.
The tallest specimen currently living is likely a tree in Sääksjärvi, Finland that was 16.40 m tall and 89 cm girth when measured in 2011 (Rasanen 2011). The tallest one ever found grew at Lake Glypen in the province of Östergötland, but it fell in a storm late in 1980; the fallen tree was measured at 18.5 m long. Another tree, locally known as "Kungen" (the King), was 18 m tall, and grew at Röshult in Värnamo. It was blown over in a 2005 storm (Jakobsson 2017).
Ages to 600 years have been reported without supporting data (Salomonson [no date]).
The seed cones are used to flavor gin (Adams 1993).
The only juniper species that occurs in both North America and Eurasia.
Jakobsson, Fredrik. 2017.07.26. The tale of the tallest common juniper. http://ents-bbs.org/viewtopic.php?f=395&t=8067, accessed 2017.07.28.
Monumental Trees. 2017. Common juniper 'Albero del poeta' at Spiaggia di Pistis - Pistis beach in Arbus. https://www.monumentaltrees.com/en/ita/sardinia/carbonia/14586_spiaggiadipistispistisbeach/, accessed 2017.07.28.
Rasanen, Kouta. 2011.11.16. European Records in Finland. http://www.ents-bbs.org/viewtopic.php?f=45&t=3272, accessed 2017.07.28.
Farjon (2005) provides a detailed account, with illustrations and details on the varieties.
Flora Celtica. [no date]. Uses of some common Scottish plants. http://www.rbge.org.uk/data/celtica/Plantuses.htm#Juniperus, accessed 2001.11.28, now defunct.
Last Modified 2017-07-28