The Gymnosperm Database

Juniperus maritima distribution map

Distribution map (Adams 2007).

There are many photos at Wikimedia Commons.


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Conservation status

Juniperus maritima

R.P. Adams 2007

Common names

Seaside juniper (Adams 2007).

Taxonomic notes

Type, Canada, British Columbia, Brentwood Bay, 48.5799°N, 123.3369°W, elev. 5 m., 2006.05.29, R.P. Adams 11056.

This species was formerly included in Juniperus scopulorum and maybe it should stay there, since the two species are essentially identical in appearance. However, both terpenoid and internal transcribed spacer (ITS) genetic sequence data clearly discriminate J. maritima from J. scopulorum and J. virginiana, two closely-related and very widespread species (Adams 2007). Moreover, these taxa join a group of seven rare Caribbean and Mexican species to form the smooth leaf margined junipers of the western hemisphere, a group of species that are so similar in appearance that a microscope and a detailed key are needed to tell them apart, unless you are an expert. The degree of genetic differentiation that sets J. maritima apart from J. scopulorum and J. virginiana is comparable to that which distinguishes other conifer species from each other, so it seems appropriate for now to recognize it as a good species. However, since genetic work to date has only succeeded in differentiating populations using ITS sequence data, this conclusion warrants further investigation by study of other portions of the genome.


Extremely similar to J. scopulorum (q.v.), except that seed cones usually mature in 14-16 months (instead of 2 years), seeds are usually (instead of rarely) exserted from the ripe cone, and scale leaf tips are obtuse (rather than varying, acute to obtuse) (Adams 2007). Trees are a uniform dark green in color, with upswept branches; J. scopulorum in contrast shows much morphological variation, with a high percentage of very glaucous specimens (A. Jacobson email 2010.04.07).

Distribution and Ecology

U.S.A.: Washington and Canada: British Columbia. Occurring around Puget Sound from Whidbey Island north to Lesqueti Island and the adjacent coast of Vancouver Island. Primarily in rocky areas near the sea coast (one known population on sand dunes). All populations are disjunct from J. scopulorum, which at its closest approach occurs at Ross Lake, BC, about 140 km to the east (Adams 2007).

"A striking aspect of the Puget Sound seaside junipers is their habitat. They all grow at the seaside (or lakeside) on granite or sand (Fig. 7). This is a very different kind of habitat than that found in J. scopulorum and J. virginiana. Juniperus scopulorum grows on dry, rocky mountainous soils. Juniperus virginiana is more cosmopolitan, growing in limestone areas as well as deep soils. Both J. scopulorum and J. virginiana are weedy junipers that invade old fields and disturbed roadsides. In contrast, the seaside juniper is not weedy and usually appears as if it is relictual (i.e., older trees, with few or no seedlings). The Puget Sound juniper's habitat seems to be very restricted and has only been collected in a few locations (Fig. 7). The Puget Sound climate is very different than the Rocky Mountain or the eastern US climates, having a mild, wet regime. In short, the Puget Sound juniper has evolved physiological genes to facilitate its growth in such an environment" (Adams 2007, p. 274).

Many junipers require or favor alkaline substrates, and alkaline soils are more common in maritime locations. Arthur Jacobson (email 2010.04.07) reports that J. maritima are doing poorly in the acidic soils at Washington Park Arboretum in Seattle, suggesting that J. maritima is another juniper that favors alkaline soils.

Big tree

One 1972 record of a 23.8 m tall specimen at Deep Cove, British Columbia (A. Jacobson email 2010.04.07).


Adams (2007) gives ring count data for seven trees. The oldest had 210 rings.




Adams (2007) provides information on several accessible populations. The best is described as a robust population of hundreds of trees that are protected in a park on Fidalgo Island, Washington; the reference is probably to Washington Park, which is just past the ferry terminal west of Anacortes. A small population on coastal sand dunes occurs south of Deception Pass at Cranberry Lake on Whidbey Island, in Deception Pass State Park.



Adams, R.P. 2007. Juniperus maritima, the seaside juniper, a new species from Puget Sound, North America. Phytologia 89(3): 263-283. Available:, accessed 2007.12.18.

See also

Last Modified 2017-12-29