Pacific Azolla
Azolla filiculoides
Last reviewed: August 2026

Toxicity unknown
Pacific Azolla (Azolla filiculoides) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
full sun
Water
high
Size
1"–3" H × 2"–6" W
Bloom
Jun, Jul, Aug, Sep
Native to
AR, AZ, CA, CO and 14 more states
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaBrowse plants for this ecoregion
Pacific azolla is a tiny floating aquatic fern that forms dense mats on water surfaces. This diminutive plant spreads rapidly across ponds and water features, turning reddish in fall and winter.
In an HOA neighborhood
Pacific Azolla takes more care to keep looking intentional in a front yard. Maintenance level: high. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Requires permanent water feature
- Can become invasive and overtake water bodies
- May be viewed as pond scum by neighbors
Wildlife value
Provides habitat for aquatic invertebrates and can serve as food for waterfowl. The dense mats offer shelter for small fish and amphibians.
Common questions
- How much sun does Pacific Azolla need?
- Pacific Azolla grows best in full sun conditions.
- When does Pacific Azolla bloom?
- Pacific Azolla blooms in June, July, August, and September.
- Where is Pacific Azolla native?
- Pacific Azolla (Azolla filiculoides) is native to AR, AZ, CA, CO and 14 more states, per the World Checklist of Vascular Plants (Kew).
- Is Pacific Azolla HOA-friendly?
- Pacific Azolla takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Pacific Azolla? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Planning a bed around it? Start a free plan with this plant
Not sure where to start? Take the 2-minute yard quiz