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Warty Caltrop

Kallstroemia parviflora

Last reviewed: June 2026

Warty Caltrop (Kallstroemia parviflora)
Photo: Wikimedia Commons (CC BY 4.0)

Light

full sun

Water

low

Size

4"–16" H × 6"–24" W

Bloom

Jun, Jul, Aug, Sep, Oct

Native to

AZ, CA, CO, IL and 8 more states

Pollinators

bees, beetles

Warty caltrop is a low-growing annual wildflower that spreads along the ground with small orange or yellow blooms from summer through fall. This native plant thrives in hot, dry conditions and requires minimal water once established. As an annual, it will reseed naturally in favorable conditions.

In an HOA neighborhood

Warty Caltrop takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

  • Low prostrate growth appears weedy
  • Common name includes 'caltrop' which sounds undesirable
  • Annual lifecycle creates gaps in landscape design

Wildlife value

The long blooming period from June through October provides nectar for native bees and beetles when many other plants have finished flowering.

Common questions

How much sun does Warty Caltrop need?
Warty Caltrop grows best in full sun conditions.
When does Warty Caltrop bloom?
Warty Caltrop blooms in June, July, August, September, and October.
Where is Warty Caltrop native?
Warty Caltrop (Kallstroemia parviflora) is native to AZ, CA, CO, IL and 8 more states, per the USDA PLANTS Database and regional native plant society lists.
What pollinators does Warty Caltrop attract?
Warty Caltrop draws bees and beetles.
Is Warty Caltrop HOA-friendly?
Warty Caltrop 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 USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow Warty Caltrop? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

Not sure where to start? Take the 2-minute yard quiz