Flower profile

Crossflower

Chorispora tenella

Introduced in the lower 48

Crossflower is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 4 states, and across the U.S. it's most often seen in bloom in March–June.

31states

4of our state lists

7,795U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Colorado, Idaho, Nevada, Utah

Quick look

Chorispora tenella is a species of flowering plant in the mustard family known by several common names, including purple mustard, blue mustard, musk mustard, and crossflower. This mustard is native to parts of Eurasia but is well known in other parts of the world, particularly in temperate regions, as an introduced species and a noxious weed.
From Wikipedia's article Chorispora tenella, CC BY-SA 4.0.

It belongs to the Brassicaceae family. ^iNaturalist
USDA PLANTS describes it as an herb (forb) with a annual life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as introduced in the lower 48 states and records it in 31 states. ^{USDA PLANTS}
NatureServe lists it as not native to Colorado, Utah, Idaho and Nevada. ^NatureServe
In Colorado, most iNaturalist sightings of it in flower come in March–June. ^iNaturalist
In Utah, most iNaturalist sightings of it in flower come in March–May. ^iNaturalist
iNaturalist has 2,662 research-grade sightings of it in Colorado, ranking #55 among the 110 flowers on our Colorado list. ^iNaturalist
iNaturalist has 1,326 research-grade sightings of it in Utah, ranking #36 among the 109 flowers on our Utah list. ^iNaturalist
iNaturalist has 739 research-grade sightings of it in Idaho, ranking #35 among the 109 flowers on our Idaho list. ^iNaturalist

Crossflower gift ideas

Handmade crossflower gifts from independent makers.

🌱 Sample spot. Handmade gift picks from independent shops will appear here once our shop partnership is approved. These cards are placeholders, not real products.

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Crossflower art print
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Crossflower greeting card
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Crossflower mug
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Crossflower earrings
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Crossflower embroidery pattern
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Crossflower sticker
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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (798 records)

Bloom time in each of our 4 states

State	Type	Peak bloom	Sightings*
Colorado	Introduced	March–June	2,662
Utah	Introduced	March–May	1,326
Idaho	Introduced	March–May	739
Nevada	Introduced	March–May	458

Conservation status

Federal (U.S. ESA): Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. ^{USFWS ECOS}
NatureServe global: GNR Not yet ranked worldwide. ^NatureServe
Colorado: No list Colorado has no state law listing endangered or threatened plants, so we show NatureServe's Colorado ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Colorado.
Utah: No list Utah has no state law listing endangered or threatened plants, so we show NatureServe's Utah ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Utah.
Idaho: No list Idaho has no state law listing endangered or threatened plants, so we show NatureServe's Idaho ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Idaho.
Nevada: Not listed Not on Nevada fully protected plants, critically endangered (NAC 527.010). NatureServe: SNA, not applicable (usually because it isn't native there) in Nevada. ^{NAC 527.010}
Rare elsewhere: No other U.S. state ranks it S1, S2, SH or SX.

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

For petsNot well documented

It isn't on the ASPCA plant list.

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records crossflower in 31 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Arizona, Arkansas, California, Colorado, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Washington, West Virginia, Wyoming.

Colorado counties with USDA records: Arapahoe, Baca, Boulder, Cheyenne, Custer, El Paso, Elbert, Jefferson, Kiowa, La Plata, Larimer, Las Animas, Lincoln, Logan, Mesa, Moffat, Montezuma, Montrose, Otero, Pueblo, Rio Blanco, Sedgwick, Summit.

Utah counties with USDA records: Beaver, Box Elder, Cache, Carbon, Daggett, Davis, Duchesne, Emery, Garfield, Grand, Iron, Juab, Kane, Millard, Morgan, Piute, Rich, Salt Lake, San Juan, Sanpete, Sevier, Summit, Tooele, Uintah, Utah, Wasatch, Washington, Wayne, Weber.

Idaho counties with USDA records: Ada, Bannock, Bingham, Blaine, Canyon, Caribou, Cassia, Elmore, Fremont, Gem, Idaho, Jerome, Lincoln, Nez Perce, Owyhee, Payette, Power, Twin Falls, Washington.