In late spring and early summer, common beargrass (Xerophyllum tenax) bursts across the mountainsides with towering stalks of bobbing blooms. Its thick flower stalks can reach from 1.00 foot/0.30 meters to over 5.00 feet/1.50 meters in height, tipped by hundreds of densely packed buds that open progressively up the stem on long, slender pedicels1A pedicel is the stem that connects an individual flower to the larger inflorescence., lending the entire bloom a whimsical, bottle brush appearance. Each individual flower is formed in parts of three: six tepals2Tepals are undistinguished petals and sepals. (Sepals are modified leaves that enclose a flower bud and are usually green, but in some species have adopted the form of petals, in which case they and the petals are called “tepals.”) and six stamens join beneath a superior ovary3An ovary is superior when it is positioned entirely above the point at which all floral components join., which is tipped with three recurved styles. After blooming, the spent flowers fold upward and mature into three-chambered capsules that contain several seeds each. The dried stalks persist into the coming year and can be used to help identify plants that are not currently in bloom.
Beargrass blooms in spring and summer, sometimes in massive displays and in other years as more of an accent feature throughout the open forests and upland meadows. Individual plants bloom sporadically from year to year. After blooming, the main clump of leaves that bore the flower spike dies back to smaller offsets around its base. Offsets and new seedlings are slow to mature, sometimes requiring several years to reach flowering size. Although some portion of the plants in a particular location will bloom in given a year, beargrass is known for its periodic “superblooms” that are likely triggered by climatic conditions that prompt simultaneous blooming in populations with high percentages of mature plants that have not yet flowered.
Common beargrass is a perennial. Its grassy, evergreen leaves grow to about 2.50 feet/0.76 meters long to form a fountain-like, basal clump that tops a thick rhizome4Rhizomes are thickened stems that grow along or under the soil surface and bear shoots above and roots below.. The leaves are bluish- or olive-green with a dull sheen, finely toothed edges, and tough, fibrous texture that enables them to weather the cycles of drought, sun, and freezing temperatures in their exposed mountaintop habitat. Smaller leaves continue up the flower stalk. Although bears are known to dig for beargrass rhizomes and tender new growth, potentially resulting in its common name, many other creatures — including humans — eat and otherwise use all parts of the plant.
Beargrass typically occurs on well-drained, poor soil in open conifer forest and sunny alpine meadows at mid- to high elevation, but is occasionally found along coastal lowlands. Plants are smaller and less prolific in shadier forest. It ranges throughout the Olympic, Cascade, and Rocky mountains, the Sierra Nevada, and the coast ranges from British Columbia south to California and east into Alberta, Montana, and Wyoming. The rhizomes easily survive moderate fire, rendering beargrass one of the first plants to regrow after its habitat has burnt. It seems to benefit from periodic removal of accumulated dry foliage and competing neighbors around the rhizome; in addition, its seeds tend to germinate better in the presence of water that has absorbed nutrients from smoke and charred material. It is thus both a survivor and pioneer species. (The beargrass in the accompanying habitat photos still flourishes in a mountaintop meadow created by a fire that destroyed the existing forest in 1958.)
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