San Diego ambrosia
Ambrosia pumila
Last reviewed: September 2026
San Diego ambrosia (Ambrosia pumila) is a perennial forb native to CA. It blooms in May, June, July, and August. The flowers draw wind pollinated.
Toxicity unknown
San Diego ambrosia (Ambrosia pumila) 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
low
Size
4"–16" H × 12"–36" W
Bloom
May, Jun, Jul, Aug
Native to
CA
Pollinators
wind pollinated
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 458 programs across 44 states, each with a link to the provider and the date we last checked it.
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A low-growing, rhizomatous perennial with grayish, finely divided leaves and small inconspicuous green flower spikes. Spreads by underground rhizomes into loose colonies on open clay flats and vernal pool margins, a rare and federally endangered species.
Growing San Diego ambrosia
Grow San Diego ambrosia in full sun and low water. Mature plants reach 4 to 16 inches tall and spread 12 to 36 inches wide.
Wildlife value
Wind-pollinated flowers offer little direct nectar value, but the plant stabilizes open clay soils that support other native vernal pool species.
Common questions
- How much sun does San Diego ambrosia need?
- San Diego ambrosia grows best in full sun conditions.
- When does San Diego ambrosia bloom?
- San Diego ambrosia blooms in May, June, July, and August.
- Where is San Diego ambrosia native?
- San Diego ambrosia (Ambrosia pumila) is native to CA, per the World Checklist of Vascular Plants (Kew).
- What pollinators does San Diego ambrosia attract?
- San Diego ambrosia draws wind pollinated.
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 San Diego ambrosia? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.