Plant of the Week
Shasta snow-wreath (Neviusia cliftonii)
By Julie K. Nelson
Imagine a large shrub growing in a national recreation area,within fifteen minutes of a town of 100,000 people, yet not known to science until 1992!
Shasta snow-wreath (Neviusia cliftonii) is endemic to northern California around the margins of Shasta Lake, north of the town of Redding, California. The environmental conditions and geographic isolation of the species suggest that it is a remnant of an old, formerly more widespread plant group. Fossil leaves of Neviusia have been unearthed in southern British Columbia. The Eastern Klamath Range, where Shasta snow wreath lives, is an ancient landscape, neither glaciated nor overlain by volcanic material, as were the surrounding Cascades, Sierra Nevada, and Trinity Mountains.
Fewer than twenty populations of this plant are known to exist, most of them small. Six of Shasta snow-wreath’s known populations were at least partly flooded by the creation of Shasta Lake after World War II. Its closest relative, Alabama snow-wreath, (Neviusia alabamensis) is a rare shrub of the southeastern United States.
The flowers of this plant are unusual in having no petals (occasionally one or two tiny remnant petals are present), and very many stamens, making the flowers look like tiny white puffs. If you visit northern California to see Shasta snow-wreath, the best time is in April or early May, when you’re likely to find it in flower, and the temperatures are mild and pleasant for hiking.
So, how did Shasta snow-wreath hide in plain sight for so long? The plant looks very similar to the common western shrubs oceanspray (Holodiscus discolor) and ninebark (Physocarpus capitatus) when not flowering. Snow-wreath flowers don’t last long. And, Shasta snow-wreath almost always grows among poison-oak, which may explain part of the mystery.