Photo: William HarmonCC BY 4.0via iNaturalistresized / cropped
Rocky Mountain Penstemon Plant Care
Penstemon strictus Benth.
Updated · Sources · How we source care data
Penstemon strictus, more commonly known as the Rocky Mountain penstemon, is a penstemon with showy blue flowers.
Every 7–10 days
Full sun to part shade
50–80°F
40–70%
At a glance
How do you care for Rocky Mountain Penstemon?
Water Rocky Mountain Penstemon every 7–10 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 50–80°F (10–27°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
Where Is the Rocky Mountain Penstemon Native To?
What Is the Rocky Mountain Penstemon?
Rocky Mountain Penstemon (Penstemon strictus) belongs to the Plantaginaceae family within the Penstemon genus. Rocky Mountain Penstemon is native to United States, Canada. Rocky Mountain Penstemon is also known as Strict Penstemon, Strict Beardtongue, Pineleaf Penstemon.
Rocky Mountain Penstemon displays an upright, clumping perennial growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Rocky Mountain Penstemon produces tubular flowers in shades of red, pink, purple, or blue.
Leaf size: approximately 4 inches.
How Often Should You Water a Rocky Mountain Penstemon?
Penstemon strictus requires watering every 7–10 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 7–10 days
Let soil partially dry between waterings
What Light Does the Rocky Mountain Penstemon Need?
Rocky Mountain Penstemon thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Rocky Mountain Penstemon Prefer?
Penstemon strictus grows best at temperatures of 50–80°F. Rocky Mountain Penstemon prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a Rocky Mountain Penstemon?
Well-draining sandy loam with added organic matter for moisture retention. Good drainage is essential for Rocky Mountain Penstemon to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Rocky Mountain Penstemon?
Feed Rocky Mountain Penstemon every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Rocky Mountain Penstemon?
Repot every 2-3 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Rocky Mountain Penstemon?
Rocky Mountain Penstemon can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to hairy beardtongue plant care, which shares the same genus.
Is the Rocky Mountain Penstemon Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Rocky Mountain Penstemon, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Rocky Mountain Penstemon?
Rocky Mountain Penstemon is susceptible to aphids, spider mites, powdery mildew. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Rocky Mountain Penstemon Need?
Rocky Mountain Penstemon grows outdoors in USDA Zone 3a – 8b. It survives winters down to planting zone 3a. Rocky Mountain Penstemon is native to United States, Canada.
Hardiness Zone
Zone 3a – 8b
Keep exploring plants
Rocky Mountain Penstemon is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Penstemon genus — compare its care with other Penstemon species on PlantoScan.
Penstemon is part of the Plantaginaceae plant family — browse all Plantaginaceae genera and species.
Rocky Mountain Penstemon thrives in bright light and direct sun — see other bright-light plants.
Related Plant Care Guides
Closely related plants with similar care requirements:
Sources
- Scientific name & taxonomy: Penstemon strictus Benth., family Plantaginaceae (first published in Prodr. 10: 324 (1846)) — World Flora Online record, IPNI name record, Wikidata.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Rocky Mountain Penstemon, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Photo: William Harmon, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 3a – 8b, estimated from the plant's typical growing conditions.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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