Koenigia davisiae, commonly known as Davis’ Knotweed or Newberry Knotweed, is a perennial herb native to alpine and subalpine zones in the western United States, particularly in Washington, Oregon, northern California, and central Idaho. It thrives in high mountain habitats such as talus slopes, fellfields, and alpine meadows, where it is adapted to the harsh conditions with a short growing season. Typically, Koenigia davisiae has decumbent or upright stems from a woody caudex and can reach up to 3 feet in height. The foliage of this species is notable for its seasonal color change, turning from green to vibrant orange to red in late summer, signaling the onset of autumn. The flowers, which bloom from July to August, are small and inconspicuous, appearing in clusters of 2 to 5 in the leaf axils.

Davis’ Knotweed is valued for its ability to add late-season color to rock gardens and alpine plantings. It is relatively low-maintenance, requiring minimal care once established in a suitable location. It prefers well-drained, rocky or sandy soils and can tolerate drought conditions, making it suitable for xeriscaping. In cultivation, it should be planted in full sun to part shade. While not commonly afflicted by diseases or pests, it can be sensitive to overwatering and poor drainage.CC BY-SA 4.0