Davis' Knotweed

koenigia davisiae

Davis' Knotweed (Koenigia davisiae) is a resilient, low-growing perennial herb native to the high-elevation regions of the western United States. Thriving in the harsh, rocky environments of the Cascade Range and the Sierra Nevada, this alpine specialist has adapted beautifully to life on shifting talus slopes and sterile volcanic pumice. It forms sprawling, leafy mats that stabilize loose mountain soils, making it an ecological anchor in fragile alpine ecosystems. What makes this plant particularly captivating is its striking seasonal transformation; throughout the summer it maintains a low profile with yellowish-green leaves, but as the autumn chill sets in, the entire plant blazes into shades of brilliant orange, red, and purple, painting the high-altitude landscapes in fiery hues.

Habitat: Found on high-elevation alpine scree, rocky talus slopes, and volcanic pumice fields, typically between 1,500 and 3,300 meters in elevation.

Appearance

Davis' Knotweed typically grows in sprawling, multi-branched clumps that reach 10 to 40 centimeters in height. Its fleshy, oval-shaped leaves are yellowish-green to bright green, with smooth or slightly hairy margins, and are arranged alternately along thick, fleshy stems. The flowers are tiny, clusters of inconspicuous yellowish-green, cream, or purplish-white blossoms nestled in the leaf axils. In late summer and autumn, the entire plant undergoes a dramatic color shift, turning a vibrant, fiery orange-red that stands out vividly against grey volcanic gravels and granite scree.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderCaryophyllalesFamilyPolygonaceaeGenusKoenigia

Davis' Knotweed

Interesting facts

By holding down loose, sandy gravels on steep mountain ridges, this plant acts as a natural erosion-control agent in fragile subalpine zones.

It thrives in some of the most barren environments in North America, including the stark volcanic ash fields around Mount Shasta and Mount Lassen.

The species is named in honor of Nancy Jane Davis, a 19th-century American botanist and educator who contributed significantly to early collections of western flora.

Special abilities

Exhibits extreme tolerance to nutrient-poor, porous volcanic ash and shifting soils where few other plants can establish roots.

Accumulates red pigments in autumn, protecting its cellular machinery from intense high-altitude ultraviolet radiation and freezing temperatures.

Develops a thick, woody taproot that penetrates deep into unstable talus slopes to anchor the plant and access subterranean moisture.

Measurements & details

Length: 10-40 cm
Lifespan: 5-25 years

Diet & Feeding

As a photosynthetic plant, Davis' Knotweed produces its own energy using sunlight, water, and carbon dioxide, while absorbing essential minerals through its root system.

Primary Foods

Sunlight
Carbon dioxide
Water
Soil minerals

Ecological connections

eaten by

American Pika

Ochotona princeps

Provides a crucial autumn food source, with its foliage gathered and dried for winter haypiles by alpine rodents.

mutualism

Western Bumblebee

Bombus occidentalis

Flowers are pollinated by high-altitude bees seeking nectar in the sparse alpine environment.

host plant

Lustrous Copper

Lycaena cupreus

Serves as a host plant and food source for the caterpillars of high-altitude butterflies.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

Collections

Collections for this object will appear here as more themes are added.

Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Davis' Knotweed?

The easiest way to identify Davis' Knotweed is to use the Snappit nature identifier app.

How long is Davis' Knotweed?

10-40 cm

How long does Davis' Knotweed live?

5-25 years

What does Davis' Knotweed eat?

As a photosynthetic plant, Davis' Knotweed produces its own energy using sunlight, water, and carbon dioxide, while absorbing essential minerals through its root system.

Where is Davis' Knotweed usually found?

Found on high-elevation alpine scree, rocky talus slopes, and volcanic pumice fields, typically between 1,500 and 3,300 meters in elevation.