How much sun does Giant Sumpweed need?

Giant Sumpweed grows best in full sun conditions.

When does Giant Sumpweed bloom?

Giant Sumpweed blooms in July, August, and September.

Where is Giant Sumpweed native?

Giant Sumpweed (Cyclachaena xanthiifolia) is native to AL, AR, CA, CO and 36 more states, per the USDA PLANTS Database and regional native plant society lists.

What pollinators does Giant Sumpweed attract?

Giant Sumpweed draws bees, beetles, and flies.

Is Giant Sumpweed HOA-friendly?

Giant Sumpweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Giant Sumpweed

Name: Pollinator Patch
Author: Pollinator Patch

Cyclachaena xanthiifolia

Last reviewed: July 2026

Light

full sun

Water

medium

Size

24"–60" H × 12"–24" W

Bloom

Jul, Aug, Sep

Native to

AL, AR, CA, CO and 36 more states

Pollinators

bees, beetles, flies

Browse plants for this ecoregion

Central Basin and Range

Giant ragweed is a tall, fast-growing annual wildflower with large, deeply lobed leaves that can reach 5 feet in height. It produces small, inconspicuous greenish flowers from July through September and thrives in sunny locations with average moisture. This native plant self-seeds readily and can form substantial colonies in favorable conditions.

In an HOA neighborhood

Giant Sumpweed 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.

Very tall and can appear weedy
Aggressive self-seeding habit
May trigger allergies in sensitive individuals

Wildlife value

The flowers attract various pollinators including native bees, beetles, and flies during its long summer blooming period. Seeds provide food for birds, particularly finches and other seed-eating species in fall.

Common questions

How much sun does Giant Sumpweed need?: Giant Sumpweed grows best in full sun conditions.
When does Giant Sumpweed bloom?: Giant Sumpweed blooms in July, August, and September.
Where is Giant Sumpweed native?: Giant Sumpweed (Cyclachaena xanthiifolia) is native to AL, AR, CA, CO and 36 more states, per the USDA PLANTS Database and regional native plant society lists.
What pollinators does Giant Sumpweed attract?: Giant Sumpweed draws bees, beetles, and flies.
Is Giant Sumpweed HOA-friendly?: Giant Sumpweed 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 Giant Sumpweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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