Giant red paintbrush

Sun

Full sun to light partial shade; afternoon shade can help in warmer gardens.

Water

Moderate; keep the root zone moist during establishment and active spring growth, without waterlogging.

Soil

Well-drained sandy, loamy or gravelly soil with moderate moisture; avoid heavily fertilised soil and stagnant winter wet.

Height

1-3 ft (0.3-0.9 m)

Spread

0.5-1 ft (0.15-0.3 m)

Flowers

Late spring through summer, depending on elevation and climate; bright red to orange-red bracts surround inconspicuous greenish flowers.

Foliage

Upright stems carry narrow green leaves, mostly undivided below and sometimes lobed toward the flower spikes; stems and leaves may be hairy.

Growth

Moderate once established; establishment is often slow and unreliable.

Care needed

High

• Pollinators
• Cold hardy
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Hard

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.2 ft (0.38 m)

3. After 2 years

   1.5 ft (0.45 m)

4. After 3 years

   1.7 ft (0.53 m)

5. After 5 years

   2 ft (0.6 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Native to

Canada

Growth rate

Slow

• Grow beside compatible living hosts, such as locally suitable fescues, tufted hairgrass or yarrow.
• Water during dry spells in the first growing season, keeping soil moist but aerated.
• Avoid routine feeding; vigorous neighbouring plants can shade and crowd it out.
• Keep mulch thin and clear of the crown; leave small patches of open soil for seedlings.
• Avoid dividing or moving established plants, which can damage their roots and host connections.

Pruning. Leave flower spikes until the seed capsules ripen if you want seedlings. Cut dead stems near ground level in late winter or early spring, taking care not to damage emerging shoots.

Autumn

Surface-sow fresh seed beside suitable host plants, pressing it onto the soil without burying it deeply.

Winter

Allow outdoor seed pots to receive natural cold, while protecting them from disturbance and waterlogging.

Early spring

Remove dead stems and check that nearby grasses are not smothering new growth.

Spring

Plant nursery-grown plants with their host roots intact; water carefully while they establish.

Summer

Water during prolonged dry spells and leave flowering spikes for pollinators and seed production.

Late summer

Collect seed when capsules turn brown and begin to split; store it dry until autumn sowing.

• Thread through a moist native meadow with fine-textured grasses for scattered red accents.
• Plant in sunny woodland openings where the soil stays cool and neighbouring vegetation is not too dense.
• Use in a western North American wildflower planting with yarrow and locally appropriate native grasses.
• Place in a naturalistic mountain garden where drainage is good but summer moisture remains available.

Garden styles it suits: Native meadow, Wildflower, Wildlife garden, Pacific Northwest woodland, Mountain lodge and Rewilded.

Plant it with: Idaho fescue, Tufted hairgrass, Bluebunch wheatgrass, Common yarrow and Selfheal.

Wildlife: The flowers provide nectar for hummingbirds within their native range and are also visited by bees. Its relationships with neighbouring plants make it especially useful in a functioning native meadow community.

• Poor establishment without suitable hosts: sow or plant among compatible grasses and herbs rather than in an isolated pot or bare bed.
• Root or crown rot in wet soil: improve drainage and keep heavy mulch away from the crown.
• Crowding by vigorous neighbours: thin surrounding growth selectively without disturbing the paintbrush roots.
• Failure to germinate: use fresh seed and provide a prolonged cold, moist period; germination can be uneven.

Toxicity to cats, dogs and people is not well documented, so do not treat it as edible. Paintbrushes can accumulate selenium from selenium-rich soils; foliage may then poison grazing animals, including horses, if enough is eaten. Risk depends strongly on the soil and amount consumed.

• Harsh paintbrush (Castilleja hispida)

  Usually has more deeply divided leaves and conspicuously stiff, spreading hairs; giant red paintbrush generally has mostly undivided lower leaves.

• Scarlet Indian paintbrush (Castilleja coccinea)

  An eastern North American annual or biennial, usually with conspicuously divided upper leaves; giant red paintbrush is a western perennial.

Castilleja honours Spanish botanist Domingo Castillejo, while miniata means vermilion-coloured, referring to the red bracts.

Propagation. Usually grown from seed. Surface-sow fresh seed outdoors in autumn, or provide cold, moist stratification before spring sowing; requirements vary with seed origin. Raise seedlings alongside suitable host plants and transplant with minimal root disturbance. Division is unreliable.

Accepted botanical name

Castilleja miniata

Native range

Alaska, Alberta, Arizona, British Columbia, California, Colorado, Idaho, Manitoba, Mexico Northwest, Montana, Nevada and New Mexico.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.