In Bloom: Superbloom!

This summer you may have noticed prodigious numbers of towering, white-flowered plants standing like sentinels throughout the Roaring Fork Valley and its mountains. Two wildflowers — Frasera speciosa, aka green gentian or monument plant, and Veratrum californicum, aka corn lily or skunk cabbage — are enjoying a “superbloom” this year.

A superbloom is a botanical phenomenon in which an unusually high proportion of wildflowers whose plants have for years been storing up nutrients in their roots and ground-level leaves, known as “rosettes,” blossom at the same time. This phenomenon is associated with an unusually wet or cool season.

Wait: 2021, wet and cool? Not! It turns out we need to look further back in time to predict this year’s superbloom.

First, let’s distinguish the two superblooming plants. Green gentian, while resembling almost not at all the small, purple, late-blooming wildflowers we usually associate with gentians, is indeed a member of that family. A close examination of one of its hundreds of elegant, symmetrical flowers, covering the full length of its three to seven-foot stalk, reveals the gentian’s characteristic four petals. Look for green gentian in sunny mountain meadows everywhere, especially in avalanche paths.

Corn lily, on the other hand, while standing similarly high, has graceful, three-dimensional, corn-like leaves swirling around its bottom half, while its smaller white flowers, six-petaled, bloom on several stalks on top and number in the thousands. It can be seen in wet meadows and aspen forests up Hagerman Pass and Capitol Creek.

To understand why both plants are enjoying a superbloom this summer, we need look no further than the Rocky Mountain Biological Laboratory in Gothic, Colorado, just a few miles south of us as the crow flies. There, Dr. David Inouye and his colleagues have been studying these and other wildflowers for decades, making some fascinating discoveries.

It turns out green gentian needs a wet summer four years prior to sending up its flower-covered stalk. 2017 was such a summer. Green gentian spends the previous 20-80 years preparing to bloom, and once it does, it will die — it is “monocarpic.”

By contrast, the scientists at RMBL believe corn lilies need a cool summer two years prior. It is not monocarpic like the green gentian. Indeed, it sends out new, underground shoots to reproduce clonally at the same time that it blooms.

Irrespective of their differences, both green gentians and corn lilies increase their odds of achieving cross-pollination and therefore long-term success by blooming in large numbers at the same time. While we will usually see a smattering of both plants in bloom each year, the odds of pollinators successfully traveling great distances between blooming plants is substantially lower during those years.

So in this year, the year of the superbloom, wish these tall beauties well, that they may grow and prosper, and that we may continue to have wet, cool summers, at least on occasion!

Karin Teague, Director of the Independence Pass Foundation, is a 25-year resident of the Roaring Fork Valley and devoted student of its wildflowers. To learn more about RMBL’s work, go to rmbl.org, or visit the Lab on your next hike to Crested Butte.