Biennial Hollyhock Plant Care
Alcea biennis Winterl
Updated · Sources · How we source care data
Alcea biennis, the biennial hollyhock, is a species of Alcea in the mallow family, Malvaceae. Synonyms include A.
Every 7–10 days
Full sun to partial shade
60–80°F
40–70%
At a glance
How do you care for Biennial Hollyhock?
Water Biennial Hollyhock 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 60–80°F (16–27°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
What Is the Biennial Hollyhock?
Biennial Hollyhock (Alcea biennis) belongs to the Malvaceae family within the Alcea genus.
Biennial Hollyhock displays a tall, upright biennial or perennial growth habit, reaching up to 6 ft tall with a spread of approximately 2 ft. Biennial Hollyhock produces large, showy blooms in various colors like pink, purple, yellow.
Leaf size: approximately 6 inches.
How Often Should You Water a Biennial Hollyhock?
Alcea biennis 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 Biennial Hollyhock Need?
Biennial Hollyhock thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Biennial Hollyhock Prefer?
Alcea biennis grows best at temperatures of 60–80°F. Biennial Hollyhock prefers humidity levels of 40–70%.
Temperature
60–80°F
Humidity
40–70%
What Soil Mix Works Best for a Biennial Hollyhock?
Well-draining loamy soil with added compost for nutrients. Good drainage is essential for Biennial Hollyhock to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Biennial Hollyhock?
Feed Biennial Hollyhock 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 Biennial Hollyhock?
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 Biennial Hollyhock?
Biennial Hollyhock can be propagated through seeds, division of rootball. Similar propagation techniques also apply to alcea digitata plant care, which shares the same genus.
Is the Biennial Hollyhock Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Biennial Hollyhock, 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 Biennial Hollyhock?
Biennial Hollyhock is susceptible to aphids, japanese beetles, caterpillars. 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 Biennial Hollyhock Need?
Biennial Hollyhock grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Biennial Hollyhock as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Biennial Hollyhock 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 Alcea genus — compare its care with other Alcea species on PlantoScan.
Alcea is part of the Malvaceae plant family — browse all Malvaceae genera and species.
Biennial Hollyhock thrives in bright light and direct sun — see other bright-light plants.
More Alcea Species
Other Alcea species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Alcea biennis Winterl, family Malvaceae (first published in Index Hort. Bot. Pest : A2 (1781)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Biennial Hollyhock, 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 13a, 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.
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