If you’ve spotted a roadside field cloaked in what appears to be freshly fallen snow, it’s not a (complete) mirage. It’s actually a hardy summer annual wildflower that begins bursting into bloom around mid-July.
In late June and early July, an intriguing plant begins to make its presence known. Solitary stems with thick green leaves begin poking up past the shaggy grasses covering vacant lots.
For many, the first inclination is to call it a milkweed, and further inspection would reveal a sticky white sap. But all is not what it seems. It’s actually the sprouts of a hardy summer annual wildflower known as snow on the mountain.
While it does not serve as a host plant for monarch caterpillars, snow on the mountain is an attractive wildlife plant that occurs naturally along many roads and in city parks.
Although it produces a similar sap to milkweed, there are a few ways to differentiate it from milkweed. The leaves of snow on the mountain have a covering of hair on the underside and pointed tips, both features that are absent on all the common milkweed species of Bexar County. The growth habit of snow on the mountain is also conspicuously different. It rises as a single stem to about two feet and then begins to branch like a fractal into successively smaller stems until each branch ends with clusters of tiny white flowers.
The leaves rather than the flowers are the showiest part of snow on the mountain. The last few sets of leaves before the blooms have bold white margins and begin appearing around mid-July and last through October. En masse they blanket fields with a white cloak, similar to fresh snow. The plant itself is toxic and deer resistant, but the seeds are eaten by game and song birds.
Snow on the mountain is easy to grow from seed. Just check the ground beneath the plants for round, black seeds about 1/8 inch in diameter. Sow them in a wildflower meadow in either spring or fall. As spring wildflowers begin to die off, snow on the mountain will be just getting started. If you can get a little colony established you’ll be rewarded with unique and consistent blooms throughout the summer, providing color and food for wildlife during the otherwise lean summer months.