Penstemon cyaneus Plant Care
Penstemon cyaneus Pennell
Updated · Sources · How we source care data
Penstemon cyaneus is a species of flowering plant in the plantain family known by the common names blue penstemon and dark blue penstemon. It is native to the western United States, where it is widespread in Idaho and also found in parts of Montana and Wyoming.
Every 7–10 days
Full sun to part shade
50–80°F
40–70%
At a glance
How do you care for Penstemon cyaneus?
Water Penstemon cyaneus 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 Penstemon cyaneus Native To?
What Is the Penstemon cyaneus?
Penstemon cyaneus (Penstemon cyaneus) belongs to the Plantaginaceae family within the Penstemon genus. Penstemon cyaneus is native to the western United States.
Penstemon cyaneus displays an upright, clumping perennial growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Penstemon cyaneus produces tubular flowers in shades of red, pink, purple, or blue.
Leaf size: approximately 4 inches.
How Often Should You Water a Penstemon cyaneus?
Penstemon cyaneus 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 Penstemon cyaneus Need?
Penstemon cyaneus thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Penstemon cyaneus Prefer?
Penstemon cyaneus grows best at temperatures of 50–80°F. Penstemon cyaneus prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a Penstemon cyaneus?
Well-draining sandy loam with added organic matter for moisture retention. Good drainage is essential for Penstemon cyaneus to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Penstemon cyaneus?
Feed Penstemon cyaneus 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 Penstemon cyaneus?
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 Penstemon cyaneus?
Penstemon cyaneus can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to foxglove beardtongue plant care, which shares the same genus.
Is the Penstemon cyaneus Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Penstemon cyaneus, 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 Penstemon cyaneus?
Penstemon cyaneus 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 Penstemon cyaneus Need?
Penstemon cyaneus grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Penstemon cyaneus is native to the western United States. In cooler regions, grow Penstemon cyaneus as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Penstemon cyaneus 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.
Penstemon cyaneus thrives in bright light and direct sun — see other bright-light plants.
More Penstemon Species
Other Penstemon species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Penstemon cyaneus Pennell, family Plantaginaceae (first published in Contr. U.S. Natl. Herb. 20: 351 (1920)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Penstemon cyaneus, 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.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- 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.
Identify Plants Like the
Penstemon cyaneus Instantly
Scan any plant with your phone camera and get instant ID, care tips, water and fertilizer reminders, and health checks — all in one app.
Free
to download
iOS & Android
platforms
Light & dark
mode
100,000+
species