Penstemon strictus
Rocky Mountain penstemon
Evergreen perennial to 75cm tall, forming large clumps of rich green, lance-shaped, slender leaves and producing upright spikes of royal blue to purple tubular flowers, over a long period from early summer
Buy this plant
Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Blue Purple | Green | ||
| Autumn | Green | |||
| Winter | Green |
Position
- Full sun
Aspect
South–facing or West–facing
Exposure
Sheltered Hardiness
H5Botanical details
- Family
- Plantaginaceae
- Native to GB / Ireland
- No
- Foliage
- Semi evergreen
- Habit
- Clump forming
- Genus
Penstemon may be deciduous or evergreen perennials or subshrubs, with simple, narrow leaves and racemes or panicles of bell-shaped or funnel-shaped flowers in summer and early autumn
- Name status
Correct
- Plant range
- United States
How to grow
Cultivation
Grow in fertile, well-drained soil in full sun or partial shade. In cold areas, protect plant overwinter with dry winter mulch. See penstemon cultivation
Propagation
Propagate by seed in late winter or spring, softwood cuttings in early summer or semi-ripe cuttings in midsummer
Suggested planting locations and garden types
- City and courtyard gardens
- Coastal
- Cottage and informal garden
- Gravel garden
- Patio and container plants
- Prairie planting
- Wildlife gardens
- Cut flowers
- Flower borders and beds
Pruning
Deadhead after flowering to maintain vigour and prolong flowering, then cut back to 15cm in late winter or early spring
Pests
May be susceptible to slugs, snails, aphids and leaf and bud eelworms
Diseases
May be susceptible to a downy mildew, grey moulds, Powdery mildews and a fungal leaf spot
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.