Penstemon speciosus
Common Name(s):
Royal Penstemon
Showy Penstemon
Synonym:
Sagebrush Penstemon
Flower:
Blue
Blooms :
Jun
to:
Aug
Tubular flowers are sky blue reaching 4 cm (1.5 in) long and about 1 cm (0.4
in) wide at the mouth.
Botanical Description
Fragrant?
NO
Family:
Scrophulariaceae
Herbaceous Plant, Perennial
Foliage:
Gray-Green
Leaves are entire and narrow
to 15 cm (6 in) long and 1 to 12 mm (0.04 to 0.5 in) wide, rounded to acute at the tip. The leaves are
mostly sessile with some of the upper leaves clasping
the stem
Fall Color?
NO
Deciduous
Photo by:
Heading 6
Oregon Native?
YES
West State Native?
YES
Origins:
Eastern WA to CA, east to ID & northeastern UT
Site Selection
Minimum USDA Hardiness Zone:
Water Needs:
VL
Sun Needs:
Full Sun
Deer Resistant?
NO
Firewise?
YES
Height:
2-2.5'
Spread:
1-2'
Growth Rate:
Medium
Native Habitat:
Royal penstemon inhabits dry flats, slopes
and draws in the sagebrush-grass, mountain shrub
and juniper forest land communities. Plants typically
occur at low to middle elevations in lowlands and
foothills from 0 to over 10,000 feet.
Soil:
Sandy or rocky soils.
Care Recommendations
Maintenance Level:
Medium
Fertilizer:
Requires no fertilizer
Mulch:
Coarse gravel, crushed rock, pea stone
Try to mimic native, nutrient poor habitat, infrequent watering in prolonged dry spells
Long Term:
Winter:
Leave some stems for frost protection and mulch with straw in winter, if necessary.
Spring:
Clear away dead winter stems, ensure fast-draining soil, no heavy fertilzing, light supplemental watering
Summer:
Cut back flowering stalks, limit watering to twice a month, ensure fast draining soil
Fall:
Reduce or stop watering, do not cut back, leave a few spent flower stems for natural seeding amd to provide food for the birds
General Care Comments:
Penstemon are low maintenance. The main requirement for success is that they need to be planted in well-drained soil-they do not like to have wet feet or crowns. They do best in lean soil without any additional amendments.
Common Problems
Waterlogged soil, poor air circulation, high humidity
Diseases:
The OSU Plant Clinic has found Phytophthora spp., Rhizoctonia spp., and Fusarium spp. associated with root rots of Penstemon spp. grown in Oregon. (https://pnwhandbooks.org/plantdisease/host-and-disease-descriptions?title=Penstemon-Root+Rot)
Insects:
Impact from insect pests on penstemon seed production can be significant. Penstemon borer larva can infect the crown and upper root area of all Penstemon species resulting in the loss of individual plants to entire fields, Penstemon weevils, Penstemon borers, Clearwing moths, Lygus bugs, raceme boring moths, seed borers, aphids, thrips, mites
Environmental Problems:
Pests:
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