Friday, September 29, 2017

Common Junipers at Castle Gardens

Not what you think when you read “castle gardens”?

After my total eclipse experience, I stayed to explore the empty country of central Wyoming, first visiting Castle Gardens at the suggestion of a friend. She had warned me: “There’s no castle and no gardens!” But in fact I found castles galore, with interesting elegant gardens, though a bit sparse. It was a pleasure to stroll, clamber, and slide back down through them.
“… the jagged edges of an eroded anticline are projected sharply above the surrounding plain … the wind has carved many of these vividly colored sandstone rocks into fantastic shapes and the landscape is dotted here and there with green pines, cedars and berry bushes, the effect is of some medieval castles surrounded by quaint gardens—hence the name Castle Gardens.” Dave Love (1)
After driving many miles on gravel roads through dry rolling “empty” country, I headed east on a rough dirt road through the “eroded anticline” that Dave Love described 85 years ago. Tilted rock layers formed multiple low ridges. The steep pale sandstone faces were fairly soft, but they were capped with resistant rock that has protected them from obliteration by erosion. But only for awhile. Eventually the protective caps will be undercut and fall away, and erosion will proceed apace.

I could see large roughly-circular patches of green scattered across the barren slopes. That’s one hardy plant, I thought, growing so vigorously where nothing else can. But what is it? I was intrigued. I hiked up a slope to check, and found a familiar shrub—common juniper! What a surprise to see it in such dry, harsh, unforgiving habitat.
Note big green patches on distant slopes.
Common juniper is indeed common here.
Erosion is an issue, along with the usual heat and drought of the high desert.
But this was only a surprise because of my perspective. I’ve seen lots of common juniper—for example in ponderosa pine forests in the Black Hills, limber and in lodgepole forests in the Laramie Mountains, and on subalpine and even alpine sites in the Medicine Bow Mountains. But I now know that common juniper must have arrived on those sites before the trees, perhaps after fire or logging or some other disturbance. For its seedlings are intolerant of shade and competition.

Common juniper generally requires open habitat to become established. It “reaches maximum abundance on harsh, stressed environments in which competition is lacking” (source). The Castle Gardens area certainly qualifies. I suspect these junipers are doing well in part because they tap into water that accumulates in fractured rocks below the surface, produced by the tilting mentioned above. I've seen this elsewhere (e.g., here).
Thriving even!

True to its name(s), common juniper (Juniperus communis) is common; in fact it's said to have “the largest geographic range of any woody plant” (source), growing throughout the northern hemisphere in cool temperate areas. In the American West we know it as a shrub, but in the northeastern USA it occasionally reaches tree size, and trees are common in Europe. This isn't just a change in size, but also architecture, with one or a few stems becoming dominant.
Juniperus communis in the Netherlands (source).
Juniper “berries” are actually cones—like tiny pine cones but with fleshy scales (you can geek out on definitions here). Berries of the common juniper are used to flavor gin. They take several years to mature, becoming blue-purple.

Back at the car: "Hot day, let’s drive somewhere and enjoy the AC!"

While many of the steep sandstone slopes were nicely sculpted, none really qualified as a castle. To see castles I continued east on the dirt road to the Castle Gardens Petroglyph Site, managed by the Bureau of Land Management (2). Amazingly there are two Castle Gardens in Wyoming. The other is near Tensleep.

The gardens among the castles were dominated by limber pine (Pinus flexilis), juniper (probably Juniperus osteosperma), and of course common juniper.
Did the limber pine get started in the protection of the common juniper?

Contrary to its name, there is an uncommonness to common juniper. It's the only juniper in North America with needles; the others have scales. But if you’re familiar with any of the scale-leaved junipers, you’ve probably seen needles on the seedlings and young growth. It's thought that common juniper has needles because it never makes the transition to mature scales. In other words, common juniper never grows up.

But I wonder if that’s really the case. The needles of common juniper (and the two other species in sect. Juniperus subsect. Juniperus) differ from the immature needles of scale-leaved junipers in that there’s a joint where they attach to the stem. In scale-leaved junipers, needles transition smoothly (photo below). Is this significant? I don't know; my online searching was fruitless. But that’s okay—I’m happy that Nature provides such interesting things to ponder.😀
Left, common juniper needles; right, immature needles of Juniperus chinensis (source).


(1) Castle Gardens used to be part of the Love Ranch, where legendary Wyoming geologist J. David Love was born and raised (featured in John McPhee’s Rising from the Plains). In 1931, while an undergraduate at the University of Wyoming, he described the site to archeologists, served as guide during survey, and provided information for their report (Renaud 1936).

(2) Vandalism of Castle Garden petroglyphs has been horrendous. It’s sad to compare today’s situation with early descriptions and photos. But the site is still worth a visit; the artwork is wonderful, and trails and fences have been built recently to protect the petroglyphs. A post about them will appear here next week.

Sources (in addition to links in post)

Randall, AG. 1964. Pictographs and petroglyphs of the Castle Gardens area, Fremont County, Wyoming. The Wyoming Archeologist 7:21-25 (PDF).


  1. Fascinating. I've always geeked out about Juniper berries for some reason, but I didn't realize they're actually cones. I'll have to study them more closely. Next time I'm out that way, I'll have to check out the Castle Gardens.

    1. I definitely recommend the Gardens. Strange that in spite of all my wanderings through WY, I hadn't been to that part. Finally got there thanks to the eclipse.