Photo: Arnim LittekCC BY 4.0via iNaturalistresized / cropped
Red Azolla Plant Care
Azolla rubra R.Br.
Updated · Sources · How we source care data
Azolla rubra is a vibrant aquatic plant with small, red leaves that float on the surface of water. Originating from Asia, this plant is popular among enthusiasts for its striking color and ability to provide natural filtration in ponds and aquariums.
Every 3–7 days
Full sun to partial shade
65°F
60–80%
At a glance
How do you care for Red Azolla?
Water Red Azolla every 3–7 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 65°F (18°C) and above and 60–80% humidity. Fertilize it every month during the growing season.
Where Is the Red Azolla Native To?
What Is the Red Azolla?
Red Azolla (Azolla rubra) belongs to the Salviniaceae family within the Azolla genus. Red Azolla is native to Australia and New Zealand. Red Azolla is also known as Red Water Fern.
Red Azolla displays a floating aquatic fern growth habit, reaching up to tall with a spread of approximately 1 ft. Red Azolla produces tiny inconspicuous sporocarps.
How Often Should You Water a Red Azolla?
Azolla rubra requires watering every 3–7 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 3–7 days
Let soil partially dry between waterings
What Light Does the Red Azolla Need?
Red Azolla thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Red Azolla Prefer?
Azolla rubra grows best at temperatures of 65°F. Red Azolla prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
65°F
Humidity
60–80%
What Soil Mix Works Best for a Red Azolla?
Nutrient-rich, muddy soil or water with high organic content. Good drainage is essential for Red Azolla to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Red Azolla?
Feed Red Azolla every month 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 month
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Red Azolla?
Not applicable, grows floating on water. 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 Red Azolla?
Red Azolla can be propagated through spores, division. Similar propagation techniques also apply to carolina azolla plant care, which shares the same genus.
Is the Red Azolla Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Red Azolla, 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 Red Azolla?
Red Azolla is susceptible to generally pest-free. 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 Red Azolla Need?
Red Azolla grows outdoors in USDA Zone 8a – 11b. It survives winters down to planting zone 8a. Red Azolla is native to Australia and New Zealand.
Hardiness Zone
Zone 8a – 11b
Keep exploring plants
Red Azolla 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 Azolla genus — compare its care with other Azolla species on PlantoScan.
Azolla is part of the Salviniaceae plant family — browse all Salviniaceae genera and species.
Red Azolla 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: Azolla rubra R.Br., family Salviniaceae (first published in Prodr. Fl. Nov. Holland. 167. 1810. Bak. Hdb. 137 (1810)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Red Azolla, 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: Arnim Littek, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 8a – 11b, 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.
Identify Plants Like the
Red Azolla 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