Woolly Blue Star Plant Care
Amsonia tomentosa Torr. & Frém.
Updated · Sources · How we source care data
Amsonia tomentosa is a species of flowering plant native to the southwestern United States and northern Mexico (Chihuahua). Its common names include woolly bluestar and gray amsonia.
Every 7–10 days
Full sun to partial shade
50–85°F
40–70%
At a glance
How do you care for Woolly Blue Star?
Water Woolly Blue Star every 7–10 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 50–85°F (10–29°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
Where Is the Woolly Blue Star Native To?
What Is the Woolly Blue Star?
Woolly Blue Star (Amsonia tomentosa) belongs to the Apocynaceae family within the Amsonia genus. Woolly Blue Star is native to the southwestern United States and northern Mexico (Chihuahua). Woolly Blue Star is also known as Blue Star.
Woolly Blue Star displays a clump-forming perennial growth habit, reaching up to 2.5 ft tall with a spread of approximately 2 ft. Woolly Blue Star produces clusters of small, star-shaped blue flowers.
Leaf size: approximately 4 inches.
How Often Should You Water a Woolly Blue Star?
Amsonia tomentosa 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 Woolly Blue Star Need?
Woolly Blue Star thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Woolly Blue Star Prefer?
Amsonia tomentosa grows best at temperatures of 50–85°F. Woolly Blue Star prefers humidity levels of 40–70%.
Temperature
50–85°F
Humidity
40–70%
What Soil Mix Works Best for a Woolly Blue Star?
Well-draining, fertile soil with a mix of sand and organic matter. Good drainage is essential for Woolly Blue Star to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Woolly Blue Star?
Feed Woolly Blue Star 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 Woolly Blue Star?
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 Woolly Blue Star?
Woolly Blue Star can be propagated through division, stem cuttings, seeds. Similar propagation techniques also apply to fringeleaf blue star plant care, which shares the same genus.
Is the Woolly Blue Star Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Woolly Blue Star, 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 Woolly Blue Star?
Woolly Blue Star is susceptible to aphids, spider mites, whiteflies. 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 Woolly Blue Star Need?
Woolly Blue Star grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Woolly Blue Star is native to the southwestern United States and northern Mexico (Chihuahua). In cooler regions, grow Woolly Blue Star as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Woolly Blue Star 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 Amsonia genus — compare its care with other Amsonia species on PlantoScan.
Amsonia is part of the Apocynaceae plant family — browse all Apocynaceae genera and species.
Woolly Blue Star 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: Amsonia tomentosa Torr. & Frém., family Apocynaceae (first published in Rep. Exped. Rocky Mts. : 316 (1845)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Woolly Blue Star, 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
Woolly Blue Star 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