Pacific Northwest Native Plant Profile: Bear Grass (Xerophyllum tenax)

X. tenax up close

When I mention bear grass, people familiar with the plant usually light up as if its creamy blossoms were right in front of their face. I’m lucky to have one in full bloom right now in my backyard (yes, just one—I have more, but they’re too young to bloom). Bear grass typically takes many years to flower, so I am savoring this one as much as possible. En masse in nature they are quite a vision, and even when not in bloom they make a lovely, luminescent, soil-stabilizing ground cover. But don’t you dare even think about taking even one plant from the wild.

X. tenax on Larch MountainBear grass, a common name for Xerophyllum tenax, comes from observations that bears like to eat the young fleshy stems, and Grizzly bears reportedly have been known to use bear grass leaves in winter dens during hibernation. It’s a popular plant for many other species who use it for food or cover: from bees and beetles to rodents and elk. Though not a true grass, other common names include Indian basket grass, deer grass, elk grass, and soap grass (not sure where the latter came from!).

The botanical name comes from the Greek xero (dry) and phyllon (leaf), and the Latin tenax (tough or tenacious). It’s an evergreen member of the corn lily family (Melanthiaceae), a group of flowering perennial herbs native to the northern hemisphere. I’ve included bear grass in my book even though it’s not terribly easy to grow. When it does establish, it spreads (very slowly) by forming offsets and by seed.

Long, skinny, and rather wiry leaves arise from the rhizome in clumps. Their edges are rough and finely serrated and it’s their toughness that helps the plant minimize water loss during periods of drought, as well as insulate it from frost.Xerophyllum tenax (foliage)

Flowers open from the bottom up, so that the inflorescence, which ranges in height from two to five feet, takes on many different shapes as it matures. Flower fragrance varies; one study reported that one-fifth of bear grass flowers in their sample had a sweet smell like cultivated lilacs, while the others smelled “musty-acrid.” The one now blooming in my yard is, thankfully, the former, although not as sweet as lilacs.

After the blossoms fade away the flowering plant usually dies, but the long-lived rhizome lives on and offsets bloom when they are mature enough. Its fruits are three-lobed dry capsules, about ¼ inch in length, that contain 6 or 7 beige seeds, which may be eaten by migratory birds prior to fall flights. They may be sown in late summer, fall or winter and need at least 12 weeks of cold stratification.

How it grows
Bear grass grows naturally in a variety of conditions—in cool, moist meadows and bogs, and mixed-coniferous forest openings in most of western Washington and Oregon, coastal areas of northern and central California, northern Idaho, parts of British Columbia and Montana, and a snippet of Wyoming. I’ve come X. tenaxacross it on hikes in the Oregon Cascades near trees such as Douglas-fir, Western hemlock, or mountain ash, and among smaller species like huckleberry, bunchberry, fawn lily, star-flowered false solomon’s seal, inside-out flower, foamflower, and woodland strawberry.

It’s often found growing on slopes (in soil that’s not particularly rich) that are moist during winter and spring, but fast draining. I grow mine on a south-facing slight slope, in partial shade. The soil’s a bit rocky and has been amended with leaf compost. Large rocks nearby help keep roots cool and moist. During very warm and dry periods I give supplemental water, especially when plants are young.

Conservation

For centuries, Native Americans valued bear grass and used it sustainably for basketry and decoration, and ate the roasted roots. Today bear grass is having a very tough time surviving with our myriad modern threats: Logging and other habitat loss, introduced forest pathogens and insects that affect associated species, fire suppression, and the floral industry that recklessly collects it for lucrative commerce (much of it is exported). If you know of a florist who uses bear grass, ask them where they got it and explain the disastrous ramifications if necessary. Never take this plant (or any other native plant) from the wild.

Bear grass is a fire resistant species that is often the first plant to grow after a fire. Like many other native plants, it needs periodic burns for strong new growth. Following a light fire that increases light, growing space, and soil nutrients, bear grass sprouts from its rhizomes, which lie just under the soil’s surface. But when fires are suppressed—often due to timber industry management—the result is fewer but much more intense fires that kill rhizomes, making it impossible for the plants to come back.

X. tenax closeWildlife value
All of these perils affect not only the species directly, but also its pollinators—nearly 30 species of flies, beetles, and bees, and possibly some butterflies, moths, and wasps. Besides pollinators, bear grass also provides food for rodents, deer and elk, and even mountain goats at higher elevations, as well as other habitat components, such as nesting material for birds, mammals, and insects—all of which are essential, interconnected ecosystem members. More info on conservation here.

Beargrass’s only close relative, X. asphodeloides, grows in the southeastern part of the U.S.

 

© 2015 Eileen M. Stark

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