Flower profile

Flower-of-an-hour

Hibiscus trionum

Introduced in the lower 48

Flower-of-an-hour 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 June–October.

46states

4of our state lists

7,978U.S. sightings*

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

On our lists for: Iowa, Kansas, Nebraska, North Dakota

Quick look

Hibiscus trionum, commonly called flower-of-an-hour, bladder hibiscus, bladder ketmia, bladder weed, puarangi and venice mallow, is an annual plant native to the Old World tropics and subtropics. It has spread throughout southern Europe both as a weed and cultivated as a garden plant.
From Wikipedia's article Hibiscus trionum, CC BY-SA 4.0.

It belongs to the Malvaceae 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 46 states. ^{USDA PLANTS}
NatureServe lists it as not native to Kansas, Iowa, Nebraska and North Dakota. ^NatureServe
In Kansas, most iNaturalist sightings of it in flower come in July–September. ^iNaturalist
In Iowa, most iNaturalist sightings of it in flower come in June–October. ^iNaturalist
iNaturalist has 407 research-grade sightings of it in Kansas, ranking #61 among the 109 flowers on our Kansas list. ^iNaturalist
iNaturalist has 340 research-grade sightings of it in Iowa, ranking #77 among the 109 flowers on our Iowa list. ^iNaturalist
iNaturalist has 178 research-grade sightings of it in Nebraska, ranking #92 among the 108 flowers on our Nebraska list. ^iNaturalist

Flower-of-an-hour gift ideas

Handmade flower-of-an-hour 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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Flower-of-an-hour art print
Gift pick coming soon
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Flower-of-an-hour greeting card
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Flower-of-an-hour mug
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Flower-of-an-hour earrings
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Flower-of-an-hour embroidery pattern
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Flower-of-an-hour sticker
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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (897 records)

Bloom time in each of our 4 states

State	Type	Peak bloom	Sightings*
Kansas	Introduced	July–September	407
Iowa	Introduced	June–October	340
Nebraska	Introduced	June–September	178
North Dakota	Introduced	few records	64

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
Kansas: No list Kansas's endangered and threatened list (K.A.R. 115-15-1) covers animals only, so we show NatureServe's Kansas ranks for plants. NatureServe: SNA, not applicable (usually because it isn't native there) in Kansas.
Iowa: Not listed Not on Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3). NatureServe: SNA, not applicable (usually because it isn't native there) in Iowa. ^{IAC 571-77.3}
Nebraska: Not listed Not on Nebraska threatened and endangered species (163 Neb. Admin. Code ch. 4, § 004). NatureServe: SNA, not applicable (usually because it isn't native there) in Nebraska. ^{163 NAC 4-004}
North Dakota: No list North Dakota has no state law listing endangered or threatened plants, so we show NatureServe's North Dakota ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in North Dakota.
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. For context only: ASPCA lists a related species, Hibiscus syriacus (“Hibiscus”), as non-toxic to dogs and cats. That doesn't tell us about this species, so keep pets away to be safe. ^ASPCA

🌿 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 flower-of-an-hour in 46 states plus Washington, D.C.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.

Kansas counties with USDA records: Allen, Anderson, Atchison, Barton, Bourbon, Brown, Butler, Chase, Chautauqua, Cherokee, Clay, Cloud, Coffey, Cowley, Crawford, Dickinson, Douglas, Edwards, Elk, Ellis, Ellsworth, Ford, Franklin, Geary, Gove, Greenwood, Hamilton, Harvey, Hodgeman, Jackson, Jefferson, Jewell, Johnson, Labette, Leavenworth, Lincoln, Linn, Lyon, Marion, Marshall, McPherson, Miami, Mitchell, Montgomery, Morris, Nemaha, Neosho, Osage, Osborne, Ottawa, Phillips, Pottawatomie, Reno, Republic, Riley, Rooks, Russell, Saline, Scott, Sedgwick, Shawnee, Sheridan, Smith, Stafford, Sumner, Wabaunsee, Washington, Wilson, Woodson, Wyandotte.

Iowa counties with USDA records: Audubon, Cass, Cherokee, Fremont, Harrison, Mitchell, Osceola, Page, Ringgold, Taylor, Washington, Winneshiek.

Nebraska counties with USDA records: Buffalo, Cass, Cherry, Cuming, Dakota, Dodge, Douglas, Franklin, Gage, Howard, Jefferson, Kearney, Knox, Lancaster, Merrick, Otoe, Pawnee, Richardson, Seward, Washington, Webster.