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California-bur

Xanthium strumarium

Last reviewed: July 2026

California-bur (Xanthium strumarium)
Photo: Wikimedia Commons (Public domain)

Light

full sun

Water

medium

Size

12"–48" H × 12"–36" W

Bloom

Jul, Aug, Sep

Native to

AL, AR, CA, CO and 40 more states

Pollinators

bees, beetles

Before you buy

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A sturdy annual forb that grows 1-4 feet tall with broad leaves and small greenish flowers from July through September. This plant produces distinctive spiny seed pods that can stick to clothing and animal fur. It thrives in full sun with average moisture and establishes quickly from seed.

In an HOA neighborhood

California-bur 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.

  • Classified as noxious weed
  • Produces painful spiny burrs
  • Looks extremely weedy and unkempt

Wildlife value

The summer flowers attract bees and beetles for pollination. The seeds provide food for birds and small mammals.

Common questions

How much sun does California-bur need?
California-bur grows best in full sun conditions.
When does California-bur bloom?
California-bur blooms in July, August, and September.
Where is California-bur native?
California-bur (Xanthium strumarium) is native to AL, AR, CA, CO and 40 more states, per vouchered herbarium specimen records and regional native plant society lists.
What pollinators does California-bur attract?
California-bur draws bees and beetles.
Is California-bur HOA-friendly?
California-bur 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 vouchered herbarium specimen records and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

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

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