When does Roman wormwood bloom?

It flowers from July through September, producing small greenish spikes of tiny flower heads.

What growing conditions does Roman wormwood prefer?

It grows best in full sun on dry, low-water sites and is commonly found in disturbed soil, fields, and roadsides.

Do insects visit Roman wormwood flowers?

Bees, beetles, and flies visit the flowers, even though the plant relies mainly on wind to move its pollen.

Is Roman wormwood a perennial plant?

No, it is an annual forb that completes its life cycle in one growing season and dies back each year.

Is Roman-wormwood HOA-friendly?

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

Roman-wormwood

Name: Pollinator Patch
Author: Pollinator Patch

Ambrosia artemisiifolia

Last reviewed: August 2026

Ambrosia artemisiifolia is an annual forb that grows in full sun with low water needs. It blooms from July through September in open fields, roadsides, and disturbed ground.

Toxicity unknown

Roman-wormwood (Ambrosia artemisiifolia) 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

12"–60" H × 6"–24" W

Bloom

Jul, Aug, Sep

Native to

AL, AR, AZ, CA and 43 more states

Pollinators

bees, beetles, flies

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 452 programs across 44 states, each with a link to the provider and the date we last checked it.

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Browse plants for this ecoregion

Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains Central California Valley North American Deserts Central Basin and Range Southern Rockies Arizona/New Mexico Mountains Chihuahuan Deserts High Plains Southwestern Tablelands Central Great Plains Great Plains Cross Timbers Edwards Plateau Southern Texas Plains Texas Blackland Prairies East Central Texas Plains Western Gulf Coastal Plain South Central Plains Eastern Temperate Forests Ozark Highlands Central Irregular Plains Northwestern Glaciated Plains Northwestern Great Plains Piedmont Northern Glaciated Plains Western Corn Belt Plains Northern Lakes and Forests North Central Hardwood Forests Driftless Area Southeastern Wisconsin Till Plains Central Corn Belt Plains Eastern Corn Belt Plains Southern Michigan/Northern Indiana Drift Plains Huron/Erie Lake Plains Northeastern Highlands Northeastern Coastal Zone Northern Allegheny Plateau Erie Drift Plain Northern Forests Middle Atlantic Coastal Plain Northern Piedmont Southeastern Plains Blue Ridge Ridge and Valley Central Appalachians Western Allegheny Plateau Interior Plateau Interior River Valleys and Hills Mississippi Alluvial Plain Mississippi Valley Loess Plains Southern Coastal Plain Southern Florida Coastal Plain Madrean Archipelago Sonoran Basin and Range Acadian Plains and Hills Eastern Great Lakes Lowlands Atlantic Coastal Pine Barrens Southern California/Northern Baja Coast

Common ragweed is a weedy annual that produces masses of wind-pollinated flowers from summer through fall. This plant is notorious for causing hay fever and seasonal allergies in many people. It typically grows in disturbed soils and can become quite tall and sprawling by late summer.

Growing Roman-wormwood

Grow Roman-wormwood in full sun and low water. Mature plants reach 12 to 60 inches tall and spread 6 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.

In an HOA neighborhood

Roman-wormwood 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.

Highly allergenic pollen causes hay fever
Considered a noxious weed in many areas
Looks very weedy and unkempt

Wildlife value

While it does attract some bees, beetles, and flies, ragweed is primarily wind-pollinated and is not considered a valuable pollinator plant. Seeds provide food for birds like goldfinches and sparrows.

Common questions

When does Roman wormwood bloom?: It flowers from July through September, producing small greenish spikes of tiny flower heads.
What growing conditions does Roman wormwood prefer?: It grows best in full sun on dry, low-water sites and is commonly found in disturbed soil, fields, and roadsides.
Do insects visit Roman wormwood flowers?: Bees, beetles, and flies visit the flowers, even though the plant relies mainly on wind to move its pollen.
Is Roman wormwood a perennial plant?: No, it is an annual forb that completes its life cycle in one growing season and dies back each year.
Is Roman-wormwood HOA-friendly?: Roman-wormwood takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.

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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