Juniperus maritima

Bent, but not broken, this seaside juniper is one of a small population of at most a couple dozen individuals growing in Washington’s Deception Pass State Park. These particular plants persisting against wind and saltspray form an atypical ecotype, as no other population is known to grow in this form and in a sand dune habitat. Typically, Juniperus maritima is an upright tree of the rocky margins of water bodies. The largest two known populations of several hundred plants each are in lands bordering Washington’s Puget Sound (another common name is Puget Sound juniper), but its range extends northward into lands adjacent to British Columbia’s Strait of Georgia. If geography is to be incorporated into a common name, a more inclusive moniker could be argued (e.g., Salish Sea juniper).

Juniperus maritima was scientifically described and published in 2007 (with a type specimen collected from Brentwood Bay, British Columbia). It may be hard to believe that a tree species near large urban areas of North America could escape the notice of botanists until 2007, but part of the reason for this is its extremely close resemblance to the Rocky Mountain juniper, Juniperus scopulorum. To be fair, Arthur Lee Jacobson (in his excellent write-up about Juniperus maritima) points out that the eminent botanist Leo Hitchcock wrote (in 1969): “Plants from the islands of Puget Sound appear to differ somewhat from those [Juniperus scopulorum] east of the Cascades in having the juvenile foliage longer-persistent and in producing cones [berries] that are less fleshy and rather consistently 1-seeded and it is believed not improbable that they will prove to constitute a distinctive race of the species.” It did take nearly 4 decades for that distinctiveness to be recognized scientifically, with convincing data coming from chemistry (terpenoid analysis) and genetics (ITS sequences).

More on the subtle physical differences between Juniperus maritima and Juniperus scopulorum can be gleaned from Botanical Electronic News #387 (January 17, 2008): Juniperus maritima, the seaside juniper, a new species from Puget Sound and Georgia Strait, North America. The original paper is available as well: Adams, R.P. 2007. Juniperus maritima, the seaside juniper, a new species from Puget Sound, North America (PDF). Phytologia 89(3):263-283). Additional photographs of this species can be seen via E-Flora BC (Juniperus maritima) or the Burke Museum Herbarium’s image collection: Juniperus maritima.

Juniperus maritima
Juniperus maritima

9 responses to “Juniperus maritima”

  1. Charles Thirkill

    Thanks for this. As always, you illuminate the mind with the awarteness of our plant communities.

  2. Charles Thirkill

    This entry reminded me of the Rocky Mountain juniper, and it is hard to believe that this is the same plant that grows at Comox Bluffs, where t5hey grow to 10 metres and more, as trees. I understand that on Texada Island, they grow even larger.
    I believe that Juniperus maritima is the tree for the future, because it is such a small tree. It would be easy to incorporate into urban forest plans for that reason, if it could be grown in sufficient quantity. We need more evergreens in our urban spaces.

  3. Adolf Ceska

    I doubt that this is Juniperus maritima. “Looks like it will have to fit under J. communis var. depressa for now.” as for the email from Robert Adams to Adolf Ceska on August 28, 2012 on similar creeping forms of such plants.
    Do you have a supporting herbarium specimen going with this photo? if not, please, make a collection of it. There are not to many collections of these plants. Their distribution goes from Texada Island through southern Vancouver Island to Whidbey Island. I may be mistaken, but this plant is not Juniperus maritima.

  4. Daniel Mosquin

    Thanks for the comments Charles and Adolf.
    Adolf, no, I didn’t collect a herbarium specimen (no permit). It is very interesting that you point out the possibility of it being Juniperus communis var. depressa, though.
    I first encountered a Juniperus at this site in the set of secondary dunes that are behind the trees you can see in the background of the second photograph. My first thought when encountering that particular creeping plant (it formed a dense creeping mat of about 10m? more? in diameter) was “Aha!”. My second thought was “No, wait, that would not be confused with Juniperus scopulorum, that looks a lot like Juniperus communis.” I then decided to explore a bit more, and found these other plants in the primary dune area and thought “That’s different, and that’s more like it.”
    Gestalt-wise, I felt like I observed two different entities. But, with Juniperus and its juvenile and mature foliage, maybe I was tricked.
    Anyway, I’ll happily go back to investigate and photodocument further. It is no hardship to spend time in Deception Pass park.

  5. Ron B

    I’ve noticed common juniper at Deception Pass before but not Puget Juniper. While the plants shown here do have a yellowish cast I don’t associate with Puget Juniper they do have more height and trunk bulk than I would expect from creeping forms of common juniper known from this region. And the two species are reported growing together in the high Olympic Mountains of Washington State.
    Both wild and cultivated examples of Puget Juniper are known with chronic twig blight or infestation issues so it is not automatically a promising ornamental. Adams reports that cones are often infested by insects, I know of very limited commercial presence of the species. And that is based on the wholesale source for the stock claiming it was Puget Juniper, without any examples of this recent distribution being large enough to display confirming adult foliage, habit and cones.

  6. Ron B

    Burke Herbarium web site does have multiple records (listed under J. scopulorum) for Deception Pass attributed to Harold W. Smith and dating from 1936, including prostrate examples growing on dunes. Thinking further since my last post there being shrubby ones among other trees there does kind of ring a bell, so I guess maybe I have seen the species on the site. I might go look this weekend.

  7. Daniel Mosquin

    Ron, regarding the height and trunk bulk, there are other plants that are yet more upright than these. This one was posted because it most appealed to my artistic sense, but here is a photo of another one:

    And here is a photo of the one I regarded as being similar to Juniperus communis. Sorry for the quality of the photos, I was dealing with harsh light.

  8. Ron B

    Although otherwise not close enough views to make out foliage details these do confirm that both species are represented, with the taller, scruffier plants being the Puget Juniper. So they grow together in Washington at near the top and near the bottom of the land. And perhaps not much, if at all between.

  9. Bill Barnes

    One easy way to distinguish close species is by looking at the seeds under a dissecting microscope , chances are J. maritime and J. scopulorum are different . Would be interesting for someone to check this . Friend and colleague at Harvard Herbarium , Julie Shaprio would love seed if any is available .

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