Living on the ledge: ingenious bitterroot

This is a story about a difficult and fascinating terrain, a beautiful, adaptable flower, and a maddening claim. Bitterroot is far from rare in the western states of the U.S. and Canada. It’s Montana’s state flower and has bequeathed its name to the Bitterroot River and Valley there. Also to the Bitterroot Mountains and the Bitterroot National Forest, which separate Montana and Idaho. It grows from northern British Columbia to southern California, and west to Colorado. For thousands of years, it was a major food source for Native Americans.

But in Marin County, just north of San Francisco, it only grows in two places, and very sparsely. One of those spots is on a small ledge of serpentine on Mount Burdell, in Novato. If I hadn’t been on a walk with Marin County naturalists both times I saw it, I would never have found it. There are tons of small rock outcroppings on walks in Marin, and sometimes they don’t even aspire to the term ‘outcrop.’ They just look like bare, rocky soil.

But this isn’t any rocky soil. Serpentine’s name comes from its dominant mineral, serpentinite. There is more of it in this area, extending north into British Columbia because it forms at the edge of old continents where tectonic plates meet. One dives under the other, scraping massive piles of rubble onto the edge of the upper plate, and taking equally massive amounts deep into the earth. After eons of heat and pressure, that rock finds its way to the surface again, the crystal structure it once had completely altered.

Among these metamorphic rocks is serpentine, noted for its blue and green coloring, though it can have other colors. Orange is common around here. Serpentine is poisonous for most plants since it contains a much higher ratio of magnesium to calcium than is usual for the earth’s crust. It also has high levels of heavy metals toxic to plants, like manganese, chromium, and nickel. 

Plants growing in the thin, pebbly soil that erodes from serpentine have to have adaptations that allow it to deal with this toxicity, and to live without the potassium and phosphorus that are crucial to most plants. Some have developed ways to selectively absorb the calcium they need, and others — called metal hyper-accumulators — have evolved to store the toxic metals in their leaves and the surrounding ground. This not only solves the problem of the excess metals but protects the plants from browsing animals and various forms of bacteria.

Some plants have adapted so well they can only live in such soils. Bitterroot is not one of these serpentine endemics, though its habitat is always rocky and dry. It solves its water needs with a large root for such a small plant, thick like a forked carrot, and very nutritious. Like many members of the Portulacaceae family, it has fleshy, almost succulent leaves and stems, which also help with water storage. These leaves go dormant in the summer, sometimes even before the flowers bloom, which also helps the plant cope with dryness from sunshine and hot rocks. The whole plant stays low to the ground, so is less affected by drying winds.

Given all these strictures — metal toxicity, water deprivation, low fertility — bitterroot’s flowers are startlingly large and lovely, opening out like waterlilies strewn on rock. They bloom briefly, and often intermittently, preferring sunny days to cloudy, and sometimes afternoons to mornings. Having seen them blooming gloriously on one spring visit to Mount Burdell, I looked forward to seeing them again.

But the following year, they seemed to be struggling. Their leaves had gone dormant by mid-month, the tips of the buds were dry, and the few flowers I found blooming were paler in comparison. All, perhaps, the result of early, unusually hot weather. And proving, once again, that loving the ephemeral beauty of wildflowers requires a certain existential fortitude.

At least I’m not depending on them for food, which the Native Americans did for millennia. And that brings us to the third part of the story: the maddening claim. Bitterroot’s Latin name is lewisia rediviva, named for Meriweather Lewis, who brought back samples (still at the Academy of Natural Sciences in Philadelphia) from his great exploration. Rediviva refers to its ability, after years in Lewis’ luggage, to revive when planted, although it never bloomed.

Naming plants for the Europeans who came across them in their travels has been standard practice ever since Linnaeus introduced botanical nomenclature in the 18th century. Given that it was a European system, that was perhaps inevitable.

What I find maddening now, however, is to read the claim that Lewis ‘discovered’ bitterroot. Here are some of the people who knew bitterroot for at least 10,000 years before Lewis:

The Washoe (California, Nevada). Owens Valley Paiute (California), Northern Paiute (California, Idaho, Nevada, Oregon), Southern Paiute (Utah). Northern Ute (Utah), Gosiute (Nevada, Utah). Western Shoshone (Idaho, Nevada, California, Utah), Northern Shoshone (Idaho, Wyoming, Utah), Eastern Shoshone (Wyoming), Salish (Idaho). The Upper Nlaka’pamux, southern Shuswap, Okanagan-Colville, and southern Kootenay of British Columbia.

North of bitterroot’s blooming range, the Nlaka’pamux, Lillooet, northern Shuswap, and northern Kootenay peoples traded for the roots, which were so valuable a bag of them could buy a horse.

The wholesale dismissal of people living here for millennia before Europeans arrived has had a thousand infinitely more dangerous and debilitating results than the claim that Lewis discovered bitterroot. But it still seems worth pointing out that this is another dismissal.

These cultures had a long and intimate relationship with the beauty and durability of bitterroot, living on its energy through the winter and timing their spring foraging migrations by its bloom. It was the second most commonly collected root for food, after camassia, the source of crucial nutrition for untold generations. And yet it’s credited to and named after a man who only mentioned it in his journals to note that he found the bitterness of the boiled roots ‘naucious to my pallate.’

It seems a little harsh to sandwich the gentle, fleeting beauty of bitterroot between the toxic realities of serpentine and the tricky prejudices of language. But there are complex and deeply interwoven histories among humans and plants, cultures and habitats, politics and policy. My Irish forebears came here because the Great Hunger of 1845-1852 devastated Ireland. The famine was caused as much by disastrous political conditions as by the fungus-like Phytophthora infestans. The latter laid waste to the potatoes that almost half of the population — because of those political realities — relied on as their sole source of food.

There are thousands of such stories in human history and more to come as climate change and population pressure alter the conditions and places in which plants can grow. These stresses will cause both strife and inventive adaptations, as plants, the earth, and humans continue their completely inseparable evolution.

I’d love to have you on the journey! If you add your email address, I’ll send you notices of new adventures.

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