Friday, June 17, 2016

Hanging Gardens at Natural Bridges

Hanging gardens in the sandstone canyon country of southeast Utah are a true niche environment. Amazing things happen in a small space.


Alcove Columbine in hanging garden, Armstrong Canyon, Natural Bridges National Monument.

They are formed by two things, primarily. One is that sandstone is porous. Water can slowly trickle down between the sand grains, even more so down all the joints in the rock (around here they had been sand dunes about 270 million years ago).

Alcove Columbine, below Kachina Bridge trailhead, Natural Bridges National Monument.

The other is that, on the Colorado Plateau in southern Utah, there are a variety of rock layers. And underneath the sandstone, sooner or later will be a much different layer. One impervious to water. Which means the water will flow sideways instead of down. Gently seeping out the side of an exposed cliff face. And there you have a hanging garden. Specially adapted plants seemingly clinging to a cliff face, or at least at the base of it.

Alcove Columbine closeup.

Since such places tend to be wet and shady, certain plants like it there. One is the Alcove Columbine, a delicately leaved and blossomed plant. Unlike their  much taller and robust cousins growing in the high mountains, these are small blossoms. They don't show off. You have to look for them in the shade of the bright high desert sunlight. 

Another hanging garden denizen is a small shrub, the Birchleaf Buckthorn - Rhamnus betulaefolia. Its almost egg shaped green leaves are distinctive in the park. A wiry stem grows from wherever the water source is, at the base of a cliff or out a crack in a face cliff.

Birchleaf Buckthorn - Rhamnus betulaefolia
In some spots, you might even find ferns. This example is on a terrace above the streambed in Armstrong Canyon. 

Ferns in a hanging garden in Armstrong Canyon at Natural Bridges.
Why ferns in a certain hanging garden but not in others? The same question can be about where Alcove Columbines and Birchleaf Buckthorn grow. Geology and soil type? Seed source? Something to ponder as you pause in the lovely shade of an overhanging cliff in canyon country.  

Photo location: Natural Bridges National Monument, southeast Utah.

© Copyright 2016 Stephen J. Krieg