Image: AI generated
American Willowherb Plant Care
Epilobium ciliatum Raf.
Updated · Sources · How we source care data
With its signature toothed leaves and vibrant pink flowers, this plant originates from North America and is a sought-after addition for plant collectors due to its unique, eye-catching appearance. Its delicate, charming flowers are a favorite among gardeners looking to add a touch of elegance to their collection.
Every 3–5 days
Full sun to partial shade
50–80°F
40–70%
At a glance
How do you care for American Willowherb?
Water American Willowherb every 3–5 days, letting the top layer of soil dry out between waterings, and give it full sun to partial 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 American Willowherb Native To?
What Is the American Willowherb?
American Willowherb (Epilobium ciliatum) belongs to the Onagraceae family within the Epilobium genus. American Willowherb is native to much of North America, southern South America, and East Asia. American Willowherb is also known as Ciliate Willowherb.
American Willowherb displays an upright, spreading perennial growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. American Willowherb produces showy spikes of pink, purple, or white flowers.
Leaf size: approximately 4 inches.
How Often Should You Water a American Willowherb?
Epilobium ciliatum requires watering every 3–5 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 3–5 days
Let soil partially dry between waterings
What Light Does the American Willowherb Need?
American Willowherb thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the American Willowherb Prefer?
Epilobium ciliatum grows best at temperatures of 50–80°F. American Willowherb prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a American Willowherb?
Moist, well-draining soil rich in organic matter. Good drainage is essential for American Willowherb to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a American Willowherb?
Feed American Willowherb 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 American Willowherb?
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 American Willowherb?
American Willowherb can be propagated through seeds, division. Similar propagation techniques also apply to square-stemmed willowherb plant care, which shares the same genus.
Is the American Willowherb Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list American Willowherb, 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 American Willowherb?
American Willowherb is susceptible to aphids, caterpillars, leaf miners. 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 American Willowherb Need?
American Willowherb grows outdoors in USDA Zone 3a – 9b. It survives winters down to planting zone 3a. American Willowherb is native to much of North America, southern South America, and East Asia.
Hardiness Zone
Zone 3a – 9b
Keep exploring plants
American Willowherb 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 Epilobium genus — compare its care with other Epilobium species on PlantoScan.
Epilobium is part of the Onagraceae plant family — browse all Onagraceae genera and species.
American Willowherb thrives in bright light and direct sun — see other bright-light plants.
More Epilobium Species
Other Epilobium species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Epilobium ciliatum Raf., family Onagraceae (first published in Med. Repos. 2(5): 361 (1808)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list American Willowherb, 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: AI-generated illustration (labelled on the image).
- Hardiness zone: USDA Zone 3a – 9b, 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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