Penstemon baccharifolius is a woody-based subshrub native to limestone cliffs and rocky slopes of the Chihuahuan Desert, ranging across Trans-Pecos Texas into northern Mexico. It produces slender scarlet tubular flowers attractive to hummingbirds from early summer through fall and tolerates extreme heat and prolonged drought once established.
Performance depends almost entirely on drainage. Alkaline, rocky, or gravelly soils suit it well; clay or any moisture-retentive mix causes rapid crown and root rot, the most common cause of failure in cultivation. Raised beds or amended slopes with crushed limestone or coarse grit replicate its natural habitat. In zone 6, a thin layer of gravel mulch over the crown buffers hard freezes without trapping moisture. The species is semi-evergreen in zones 8 and warmer and handles dry summer heat without wilting or foliar stress that afflicts many other penstemons.
The flower shape is closely matched to hummingbird bill morphology, making this one of the more reliable hummingbird forage plants in xeric and southwestern-style gardens, particularly during midsummer when few other species are in flower.
Ecoregions:Great PlainsNorth American Deserts
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
Crown Rot
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.
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.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.