How much sun does Hayfield tarweed need?

Hayfield tarweed grows best in full sun conditions.

When does Hayfield tarweed bloom?

Hayfield tarweed blooms in May, June, July, and August.

Where is Hayfield tarweed native?

Hayfield tarweed (Hemizonia congesta) is native to CA, OR, per vouchered herbarium specimen records and regional native plant society lists.

Hayfield tarweed

Name: Pollinator Patch
Author: Pollinator Patch

Hemizonia congesta

Last reviewed: September 2026

Hayfield tarweed (Hemizonia congesta) is a annual forb native to CA, OR. It blooms in May, June, July, and August. The flowers draw bees.

Toxicity unknown

Hayfield tarweed (Hemizonia congesta) 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

8"–24" H × 8"–12" W

Bloom

May, Jun, Jul, Aug

Native to

CA, OR

Pollinators

bees

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Browse plants for this ecoregion

Coast Range Sierra Nevada Central California Foothills and Coastal Mountains Central California Valley Southern California Mountains Northwestern Forested Mountains Southern California/Northern Baja Coast

A sticky aromatic annual forb with narrow leaves and cheerful yellow daisy-like flowers through the dry season. Common in grasslands and disturbed open ground, growing sparser and stickier late in the year.

Growing Hayfield tarweed

Grow Hayfield tarweed in full sun and low water. Mature plants reach 8 to 24 inches tall and spread 8 to 12 inches wide.

Wildlife value

Extends summer nectar availability for bees when many other annuals have finished blooming.

Common questions

How much sun does Hayfield tarweed need?: Hayfield tarweed grows best in full sun conditions.
When does Hayfield tarweed bloom?: Hayfield tarweed blooms in May, June, July, and August.
Where is Hayfield tarweed native?: Hayfield tarweed (Hemizonia congesta) is native to CA, OR, per vouchered herbarium specimen records and regional native plant society lists.
What pollinators does Hayfield tarweed attract?: Hayfield tarweed draws bees.

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.

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.

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