Castilleja angustifolia, commonly known as Northwestern Indian Paintbrush, is a perennial herb native to the arid and semi-arid regions of western North America, including desert scrublands, sagebrush steppe, and open woodlands. It is particularly adapted to hot, sandy soils and rocky crevices, thriving under dry conditions. This species typically reaches less than half a meter in height and is characterized by its bristly gray-green to purple-red foliage. The tubular yellow-green flowers are subtended by bright red to orange-red bracts, which are highly attractive to hummingbirds and butterflies, serving as a food source and facilitating pollination. Castilleja angustifolia blooms from May to September, adding vibrant color to the landscape during these months.

In cultivation, Northwestern Indian Paintbrush is valued for its drought tolerance and unique floral display, making it a suitable choice for xeriscaping, rock gardens, and native plant gardens. It requires minimal maintenance once established and prefers full sun to part shade, with well-drained soils. While it is not commonly used in traditional horticultural settings, its striking appearance and ecological benefits, such as providing nectar for pollinators, make it an appealing addition to naturalistic plantings. Care should be taken when cultivating this species, as it is semi-parasitic and may require a host plant to thrive. Overwatering and rich soils can be detrimental to its health.CC BY-SA 4.0