Photo: Tom ScavoCC BY 4.0via iNaturalistresized / cropped
Blue Cohosh Plant Care
Caulophyllum thalictroides (L.) Michx.
Updated · Sources · How we source care data
Caulophyllum thalictroides, the blue cohosh, is a species of flowering plant in the Berberidaceae (barberry) family. It is a medium-tall perennial with blue berry-like fruits and bluish-green foliage.
Every 7–10 days
Partial to full shade
50–75°F
40–70%
At a glance
How do you care for Blue Cohosh?
Water Blue Cohosh every 7–10 days, letting the top layer of soil dry out between waterings, and give it partial to full shade. It prefers temperatures of 50–75°F (10–24°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
Where Is the Blue Cohosh Native To?
What Is the Blue Cohosh?
Blue Cohosh (Caulophyllum thalictroides) belongs to the Berberidaceae family within the Caulophyllum genus. Blue Cohosh is native to Eastern North America, United States, Canada. Blue Cohosh is also known as Papoose Root, Blueberry Root.
Blue Cohosh displays a clumping herbaceous perennial growth habit, reaching up to 1.5 ft tall with a spread of approximately 1 ft. Blue Cohosh produces small, greenish-yellow flowers in spring.
Leaf size: approximately 6 inches.
How Often Should You Water a Blue Cohosh?
Caulophyllum thalictroides 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 Blue Cohosh Need?
Blue Cohosh thrives in partial to full shade. The optimal light range is 100–1,000 lux. Avoid placing Blue Cohosh in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Partial to full shade
100–1,000 lux
What Temperature and Humidity Does the Blue Cohosh Prefer?
Caulophyllum thalictroides grows best at temperatures of 50–75°F. Blue Cohosh prefers humidity levels of 40–70%.
Temperature
50–75°F
Humidity
40–70%
What Soil Mix Works Best for a Blue Cohosh?
Rich, moist, well-draining soil with high organic matter content. Good drainage is essential for Blue Cohosh to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Blue Cohosh?
Feed Blue Cohosh 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 Blue Cohosh?
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 Blue Cohosh?
Blue Cohosh can be propagated through division, seeds.
Is the Blue Cohosh Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Blue Cohosh, 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 Blue Cohosh?
Blue Cohosh is susceptible to aphids, slugs, snails. 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 Blue Cohosh Need?
Blue Cohosh grows outdoors in USDA Zone 3a – 8b. It survives winters down to planting zone 3a. Blue Cohosh is native to Eastern North America, United States, Canada.
Hardiness Zone
Zone 3a – 8b
Keep exploring plants
Blue Cohosh 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 Caulophyllum genus — compare its care with other Caulophyllum species on PlantoScan.
Caulophyllum is part of the Berberidaceae plant family — browse all Berberidaceae genera and species.
Blue Cohosh copes with lower light than most plants — browse the full list of low-light plants.
Related Plant Care Guides
Closely related plants with similar care requirements:
Sources
- Scientific name & taxonomy: Caulophyllum thalictroides (L.) Michx., family Berberidaceae (first published in Fl. Bor.-Amer. 1: 205 (1803)) — World Flora Online record, IPNI name record, Wikidata.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Blue Cohosh, 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: Tom Scavo, 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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