Scrophulariaceae: Castilleja angustifolia var. dubia
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Family Name
Scrophulariaceae (Orobanchaceae)
Common Name
Narrowleaf Indian paintbrush, desert paintbrush
Description
Castilleja angustifolia var. dubia is a perennial herb growing from a woody, branching taproot and may form small clumps. Stems are erect, simple or occasionally branched near the base, typically 10–40 cm tall, and covered with short, soft, grayish or white hairs (pubescent). Leaves are alternate, narrow, linear to lanceolate, 2–6 cm long and 1–5 mm wide, entire or with a few shallow lobes, and are also softly hairy. Only cauline leaves are present; there is no basal rosette. Flowering occurs from late spring to early summer (May–July). Inflorescences are terminal, forming dense, spike-like clusters of brightly colored bracts and small, tubular flowers. Bracts are bright red to orange-red (sometimes yellow), 1–2.5 cm long, and often deeply divided at the tip. The actual flowers are inconspicuous, tubular, greenish to yellowish, 2-lipped, and about 1.5–2.5 cm long, partly hidden among the bracts. Each flower has a calyx with four lobes, a tubular corolla, four stamens, and a single style. The fruit is a small, oval capsule (8–12 mm) containing numerous tiny, brown, dust-like seeds, maturing in midsummer. Narrowleaf Indian paintbrush is native to South Dakota, particularly in dry prairies, sagebrush flats, rocky hillsides, and open pine woodlands. It is most commonly found in the western part of the state, including the Black Hills and Badlands.
Synonym: Castilleja chromosa
Horticulture Notes
Seed Collection: Seeds are mature when capsules turn brown and begin to split; collect before seeds are wind-dispersed, usually in midsummer.
Germination: Seeds require exposure to light and benefit from cold stratification (30–60 days) for best germination; sow on the soil surface in fall or after stratification in spring. Germination and establishment are much higher when sown near compatible host plants (native grasses or forbs).
Vegetative Propagation: Not commonly propagated vegetatively; mostly grown from seed.
Soils: Prefers well-drained, sandy or rocky soils and tolerates poor, dry substrates.
Light: Thrives in full sun.
Water: Drought-tolerant; requires minimal supplemental water once established, but adequate moisture is important during germination and initial establishment.
Additional Notes
Narrowleaf Indian paintbrush is native and prized for its vibrant color in native plant gardens, prairie restorations, and wildflower meadows. It is a hemiparasite, obtaining some nutrients from the roots of neighboring grasses and forbs, which should be considered in cultivation. The plant attracts hummingbirds and some native bees. Some Indigenous groups have used Castilleja species as a dye.