PL. —Penstemon centranthifoliusBotanical illustration — drop image
Penstemon centranthifolius

Scarlet Bugler

SpringSummer
7a10bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
In bloom
Summer
Peak bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Penstemon centranthifolius is a California native perennial producing tall upright stems lined with narrow scarlet tubular flowers from spring into early summer. It occurs naturally across coastal scrub, chaparral, and oak woodland from central California into Baja California, tolerating poor, rocky, and very dry soils. Gardeners in Mediterranean-climate regions value it for drought tolerance, stability on slopes, and reliable hummingbird attraction.

Once established, it requires almost no supplemental irrigation and thrives in full sun with sharp drainage. It grows readily from seed sown directly in fall, relying on winter rains for germination. Crowns rot quickly in waterlogged or clay-heavy soil; amend with coarse grit where drainage is marginal. Plants are typically short-lived at 3–5 years but self-seed freely where conditions suit them.

The narrow tubular flowers are shaped for hummingbird pollination and support migrating and breeding hummingbirds through spring and early summer. Native bees also visit the flowers.

Care guide
SunFull sun
WaterLow
SoilWell-drained, dry, sandy or gritty, low fertility
Spacing18–24 in
Height24–48 in
Zone7a – 10b
Native RegionAZ, CA
Direct sowFrost hardy
Seasonal tasks
winter
watchMonitor soil drainage around plant crowns during wet periods; standing water leads rapidly to crown and root rot.
spring
sowFor spring establishment, cold-stratify seeds in damp sand at 35–40°F for 4–6 weeks, then direct sow after last frost.
watchInspect foliage for powdery mildew in late spring, particularly where plants are crowded or air circulation is poor.
summer
cutCut spent flower stalks back to basal foliage after bloom ends; leave a few stalks standing if self-seeding is desired.
sowPlant container-grown starts in fall, 6–8 weeks before first frost, so roots establish before summer drought stress begins.
fall
sowDirect sow seeds on a raked, well-drained seedbed in fall; cold winter rains trigger germination naturally without additional treatment.
Common problems

Fungal leaf spot

Symptoms

Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.

Treatment

Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.

Crown Rot

Symptoms

Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.

Treatment

Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.

Phytophthora Root Rot

Symptoms

Wilting despite moist soil, yellowing leaves, stunted growth, and dark, decayed roots and crown tissue. Vines may collapse during hot weather.

Treatment

Plant in well-draining soil and avoid waterlogging. Remove and destroy affected vines. Improve drainage with raised beds or amended soil and avoid overwatering.