Hibiscus trionum (Flower of an Hour)

Plant Info
Also known as:
Family:Malvaceae (Mallow)
Life cycle:annual
  • Weedy
Habitat:sun; fields, roadsides, waste areas
Bloom season:July - September
Plant height:4 to 24 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 5-petals

[photo of flower] Flowers are 2 to 2½ inches across with 5 round, overlapping pale yellow petals, deep purple at the base. In the center are many bright orange tipped stamens and a stigma rising up in the center with 5 deep red, fuzzy round branches at the tip. Behind the flower are 5 translucient sepals, starkly veined with stiff hairs on vein ridges. Up to 12 narrow, spreading, hairy bracts sit below. Flowers arise on hairy stalks from leaf axils in the upper part of the plant

Leaves and stem: Leaf attachment: alternate Leaf type: compound Leaf type: lobed Leaf type: palmate

[photo of leaves] Leaves are up to 3 inches long and 2 inches wide, palmately compound mostly in 3's, each leaflet with rounded lobes and the end leaflet largest. Stems are branched at base, sparsely wooly, semi-erect or sprawling.

Fruit: Fruit type: capsule/pod

The sepals persist and enclose a 5-sectioned capsule containing brownish black, kidney-shaped seeds.


Flower of an Hour is an increasing field/garden/roadside pest in Minnesota, the flowers are quite beautiful, lasting only briefly in the day. It was once considered a county-level noxious weed and agricultural pest, but Round-up Ready crops took care of that.

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More photos

Photos courtesy Peter M. Dziuk, taken in cultivated fields in Anoka and Dakota Counties


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Theresa - my flower bed
on: 2010-06-30 10:49:07

I purchased a package of wildflowers 2 years ago and these were in there. I left them grow and they come back every year. My father-in-law just pulled all of them out though.

Posted by: K. Chayka
on: 2010-06-30 16:41:30

That is a continuing problem--invasive species are still sold in seed packets (mail order, especially) and in garden centers. Most people don't even realize they're buying weeds.

Posted by: Kelly - Shakopee
on: 2011-07-06 14:29:59

I have no idea where these have come from. I LOVE them I look forward to each flower when it blooms. It is in a contained rock bed and so it hasn't spread very far in 5 years. Actually, I am intentionally spreading it through out th rocks.. is this bad?

Posted by: K. Chayka
on: 2011-07-06 18:12:36

Kelly, I just want to comment on your first statement: "I have no idea where these have come from". See, this is the problem. They escaped from somewhere else and landed in your yard. Don't be fooled into thinking they are not escaping from your yard and landing somewhere else, because that is what invasives do.

You may think you have them contained but you don't really. Seed is transported elsewhere by wind, water and critters and unless you keep them indoors they will end up in the landscape outside of your yard. They are a noxious weed. Pretty, maybe, but a weed nonetheless. There are so many wonderful native species you might have in your garden. Why not plant some of them instead?

Posted by: John - Cottage Grove (Washington County)
on: 2011-07-31 13:46:40

I seeded a wild flower mix along a transition between my lawn and a 1 acre pasture 5 years ago. I tilled and planted pumpkins in that field the last 2 years. This year I tilled and reseeded with a high purity Clover-Timothy Blend. This species is now populated throughout this new clover-timothy field, but it did not come from the new seed, as this is the only field with this species between the 2 fields I reseeded. I was not concerned but after reading above,I hope it will be crowded out as I mow the pasture 2-3 times per season for weed control.

Posted by: Bonnie - Cannon Falls
on: 2011-09-03 17:39:03

We live next to the woods and have a lot of birds and critters in the area. I am guessing that a bird or a bunny dropped a couple of seeds in my small watermelon patch or it somehow got into the watermelon seed pack. They were allowed to grow because at first, their leaves looked similar to baby watermelon, and then when they surprised me with their beautiful little flower, I let them live. Quite pretty actually. Living here for years, we gave up struggling to completely keep out the invasive wildflowers from the woods. Life's too short.

Posted by: Pyllis - Menahga (north central)
on: 2012-08-28 17:26:13

One was found in our Memorial Garden in our city. None of us knew what it was, so I went on-line to check it out. Quite pretty, considering what a bad rep it gets!

Posted by: Carole - Maplewood, MN
on: 2012-10-25 21:10:25

Found growing in a rain garden in N. Maplewood. I will urge the homeowner to dig it up.

Posted by: Nissa - Champlin
on: 2013-08-08 12:43:33

I have these flowers/weeds coming up all over in my annual beds. I thought they were pretty too, but I have since dug them all up and replaced them with something that is non-weedy. I have no idea where they came from either, but I'm the only one that had them on my cul-de-sac.

Posted by: Douglas - Marsh Lake Swift County
on: 2014-07-27 13:22:27

Found a small patch on edge of a food plot in Lac qui Parle WMA at Marsh Lake. Very beautiful flowers. They definitely stand out. Too bad they're a pest.

Posted by: Susan - Monticello, Wright County
on: 2014-08-03 11:20:34

Found in my yard several years ago. If you like the plant and want it in your flowers you should be able to control the spread of it by removing all of the seed heads once the flower has expired, not allowing the seeds to ripen and mature. I have always enjoyed the blooms and call it my "weekender flower" since I only see the blooms mid to late morning on days that I am not at work.

Posted by: Rose - Cottonwood County
on: 2015-05-20 17:20:16

One of the many garden pests in this area.

Posted by: Shelly - Wright County
on: 2015-09-04 05:33:29

Hundreds of these plants are growing in the farm field adjacent to my property. Because the price of corn is low my neighbor planted wheat and must not have used Round-up.

Posted by: Starr - Linden Hills, Minneapolis
on: 2015-09-09 19:42:32

Dang it! This plant is so pretty and I have no idea where it came from. Well, non-native, invasive plants have to go. Perhaps I can patio plant it and pick pods before they can seed. That deep fuscia center is pretty.

Posted by: Kimberly - Cottonwood County
on: 2017-03-16 15:10:11

Garden pest.

Posted by: Jeremiah A - Lyon county South of Lynd, MN
on: 2017-09-21 11:30:55

Hibiscus trionum (Flower of an Hour) found in garden...

Posted by: Joellen K - Nashville, Michigan
on: 2018-08-05 11:46:47

This showed up in my raised bed where I am growing tomatoes.

Posted by: Cindy Holzinger - Anoka County
on: 2019-07-23 16:17:28

I think I have 1 single plant where I planted lavender seeds I also amended soil with compost. I am still uncertain flowers opening briefly early day but from pictures Hibiscus Trionum seems to be the plant I have never seen before. I will look at bloom tomorrow and if confirmed will be pulling out of my herb garden.

Posted by: Therese Jacobson - Alvarado
on: 2019-07-28 13:55:32

I walk our rural road often, taking photos of wildflowers. Hibiscus Trionum appeared for the first time ever this week near wheatfields alongside a new 6-foot culvert. Another newcomer is daisies, which are also noxious to some animals. Installing the culvert may have brought seeding.

Posted by: Linda M Sherbo - Des Moines, IOWA
on: 2020-07-03 11:00:02

discovered this in my garden,I didn't know what it was, I suspected it was a wild flower but it flowers very little but mostly spreads more and more every year. I wonder if it could have come to my garden in the compost or other enrichment additive I used. How can I get rid of it, so its not soaking up moisture I need in there for my vegetables I grow.

Posted by: K. Chayka
on: 2020-07-03 13:49:52

Linda, try pulling/digging, but if it's been there for several years you'll probably have a seed bank to contend with for some years yet.

Posted by: Michael Schroeder - Mounds View
on: 2021-08-02 09:14:56

These plants have popped up in dirt that was brought in to fill in where I had 2 stumps removed. This is my first summer at our house, but I'm not seeing them in any other areas of the yard. I will be pulling them and bagging them to keep the seeds from getting out.

Posted by: Susan Stanich - far west Duluth (Old Fond du Lac)
on: 2021-08-19 11:02:36

It just appeared in my mostly vegetable garden this year, An intriguing plant - but after reading this, I'll pull it out. Thank you.

Posted by: Charlene Nelson - Grant county
on: 2021-09-09 21:03:34

Found on a mowed area growing close to ground. Photo available

Posted by: Jesseca Hunt - Coon Rapids, MN
on: 2022-08-29 16:48:17

I just started having these pop up in garden box. I had to ask what they were since I had not planted them.

Posted by: Renee Hahn - Cosmos mn
on: 2023-07-18 21:22:53

I do believe that mine came from a wildflower packet that I bought. This is the first year that I have them come up. I live in town. I will not pull them out unless they overtake my other flowers. I don't bellieve that is illegal to do? Please correct me if I'm wrong.

Posted by: K Chayka
on: 2023-07-19 07:38:10

Renee, it is not illegal to sell or propagate weeds, except for specific species as designated by the MN Dept. of Agriculture.

Posted by: Todd B - Carver County
on: 2023-08-19 22:04:59

These are a pervasive weed in the garden plot that I use. They are everywhere, and any open soil that is not actively cultivated and consistently weeded is overflowing with these.

Posted by: billy bob - saint paul
on: 2023-08-31 13:17:21

hello pretty flower

Posted by: Kim - Rochester-olmsted county
on: 2023-09-12 09:16:52

My neighbor called me over to ask if I knew what this plant was. She is 93 and has been gardening in this same neighborhood for most of her life and has never seen it before. Should I tell her to pull it up? Not sure what a noxious weed is but I don't really want it spreading to my flower garden.

Posted by: Alisa - NE Minneapolis
on: 2024-03-12 18:01:43

Does it crowd out other plants? It seems so wimpy! Also, where did it come from?

Posted by: K Chayka
on: 2024-03-12 18:25:35

Alisa, per the table of plant info at the top of the page: it's weedy (more than invasive), and it's from Europe.

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