hibiscus weed

Hibiscus Species, Bladder Hibiscus, Flower of an Hour, Venice, Venus Mallow

Hibiscus trionum

Family: Malvaceae (mal-VAY-see-ee) (Info)
Genus: Hibiscus (hi-BIS-kus) (Info)
Species: trionum (try-OH-num) (Info)

» View all varieties of Hibiscus


24-36 in. (60-90 cm)


12-15 in. (30-38 cm)

15-18 in. (38-45 cm)

18-24 in. (45-60 cm)

Sun Exposure:
Bloom Color:

Scarlet (dark red)

Bloom Time:

Late Summer/Early Fall

Other details:

May be a noxious weed or invasive

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:
Propagation Methods:

From seed; sow indoors before last frost

From seed; direct sow after last frost

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

Properly cleaned, seed can be successfully stored

Foliage Color:
Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

This plant is said to grow outdoors in the following regions:

San Jose, California

Canon City, Colorado

Cherry Valley, Illinois

Graham, North Carolina

Columbia Station, Ohio

Newtown Square, Pennsylvania

Mc Kinney, Texas

South Milwaukee, Wisconsin

Gardeners’ Notes:

On Sep 4, 2015, 49erfan33 from Yukon, OK wrote:

I’m in Oklahoma and I was surprised to see this pop up in our small strawberry patch the first year. The plant/weed grows quickly and I’m probably too late to keep it from seeding.

Also worth noting, the flowers only bloom early in the day for a few hours and then after 2 or 3 days, they’re dead. Probably not worth keeping around.

On Mar 9, 2014, jillwozhere from Perth,
Australia wrote:

I live near Perth Australia and I just noticed this plant in my veggie garden yesterday. I didn’t recognise the leaves and decided to wait for the flower. I didn’t have to wait long, as it flowered the very next day! Still I did not know this plant, so searched for it online by description. At first I was quite delighted by this pretty little flower, but now I have to be worried as it sounds like hard work if I keep it. I guess I’ll have to pull it out. I wonder where the seed came from? Years ago I added soil mix to the yard, but since have been using my home made compost. I did add some bentonite clay last year, but previous to the veggie garden the area was just lawn. I’ve lived on my rural property for 30 years and never seen this flower until today. pity it goes crazy.

On Jul 18, 2013, sharilynncammac from Buhl, ID wrote:

hmmmmm, not sure-pretty little wildflower or evil multiplying weed. I just don’t know what to do next with mine. In Buhl, Idaho.

On Sep 23, 2012, JDahmer2 from Waltham, MA wrote:

I found the Flower of the Hour, or Venice Flower at our job site in Wayland, Massachusetts. I think that it is a neat flower. Never seen one before. I dug it up, just in time. The concrete truck dumped it’s excess of concrete in the spot this plant was growing in. I have it on my balcony.

On Sep 10, 2009, Jaketheplantman from Dover, PA wrote:

I just found this plant growing near one of my flower Garden’s. At first i thought it was a Mallow Musk because of the leave’s. I Transplanted it in a pot and move it to my Green House. One day it flowered and was surpise. The plant wasn’t a Mallow Musk but a Flower of and Hour. Now i readed other People’s Opinion about the plant and they call it a weed and i know this plant will spread by seed. But if you take the time to cut the spent flower heads it can’t spread. And doesn’t a Columbine do the same if you leave the flower heads on. So really I think its a neat plant to add with the rest of my Garden and to the Mallow Family Plants like Rose Mallow, Large Mallow, HollyHocks and Marsh Mallow. All i also have seeds that i collected form another plant that i found Transplanted in my gar. read more den

On Jun 29, 2009, quasymoto from Bloomfield, IA (Zone 5b) wrote:

As an avid gardener (veggies and flowers) I have fought for years to YANK these out of my gardens where my veggies grow. I guess I never notice it anywhere else in the yard and or flower gardens. But this can and will take over, but a good tiller w/plenty of horse power keeps the buggers from even getting more than a few leaves on.

The pictures on here are far more prettier than in person, and I never took much notice of how long the bloom was for. I just know it preferred to grow where I didn’t want it.

Quasy in S.E. Iowa

On Sep 29, 2008, ChemicalFlux from Minneapolis, MN wrote:

I have never seen this plant before this summer. We brought home a truck-load of dirt to do some landscaping and I believe that this seed was brought to our yard through the black dirt we laid. It has only started to grow where we laid the new dirt.

Before they started to bloom, I was pulling them out of the yard but I got a little behind on the weeding and found a few flowering one morning. I had no idea what they were but I thought they were pretty so I left them. They bloom in the morning hours at different times, it seems it is dependent upon how much light is hitting them – all of them are closed by noon.

I am planning on making a native species wildflower garden in the spring so I am going to leave a few of them but just control their growth by pullin. read more g up the new plants. I think as long as I mix longer blooming flowers that grow at the same height – the weedy look they get after the flowers close will not be a large issue.

Thanks for all the other opinions!

On Jun 22, 2008, CountryGardens from Lewisville, MN (Zone 4a) wrote:

I can’t believe this weed is even listed here. It is terrible! The only good is when soybean aphids arrive, it is the first plant they attack. Then when you are pulling them, you get nice sticky goo all over you!

It will chock out your good plants.

On Jan 28, 2006, Equilibrium wrote:

Indigenous to Europe, Flower Of An Hour loves disturbed areas and flourishes in them. This plant will probably end up on noxious weed lists sooner or later at the rate I’m seeing them pop up here there and everywhere. The flowers aren’t even that showy and they aren’t open all that long. Perhaps around a half hour early in the morning and after that all you get to see is scraggly foliage sprawled out over the ground. Good thing is that it is an annual so if you keep pulling it up, sooner or later you’ll beat back the seed bank.

On Oct 30, 2005, aasplus from Lordstown, OH (Zone 5a) wrote:

I’m with JEFE. I had never seen this plant until after we had our sewer line put in. I must admit I think the flower is beautiful, I have seen many of them bloom, each time I made a mental note and tried to find out what it was. After 4 years I found it on the internet with many warnings, it is an invasive weed. The seeds came be dormant for 50 years the are where these started to grow had not been touched in 23 years so crunch those numbers. All it took was the rain and a little sun and they invaded like Atilla the Hun. I just found out they were a weed today but I sort of knew that several years ago when they came out like gangbusters. The flowers bloom quickly but the seeds grow and spread quicker. The name is Venice Mallow (Flower of an hour) (Hibiscus trionum) I found the info on Wee. read more
This plant needs to be tacked up on the Post Office Bulletin Board. Another good thing I can say on the plants behalf is, the tap root is easy to pull out. I’m sorry to burst your bubble about this pretty little flower but I like to personally choose the plants for my flower beds, I must admit I let a few grow but when I couldn’t keep up with the seed production I started the evacuation process which is still going on after 4 years.
I feel better now. Thanks for the chance to get that off my chest.

On Sep 6, 2005, jansong from South Hadley, MA (Zone 5b) wrote:

One plant came up in my garden outside of Philadelphia, PA this summer and it has taken weeks for me to identify it. Maybe it will become the invasive problem that others write about, but this beautiful flower is a joy the few hours it comes out.

On Dec 30, 2004, JefeQuicktech from Moorhead, MN (Zone 4a) wrote:

I have a tough time considering Canada Thistle as a weed. However, Flower Of An Hour, Venice Mallow Hibiscus trionum is a WEED. It is not just invasive in our garden it is EVIL, bad, malo, muy malo, inicuo.

Before I identified this weed and knew what it was, I have literally checked every half hour looking for blooms. Thinking it was some really cool, rare plant. Oh! You Venitian Vixen you fooled me. Flower of an hour? Try flower of a second! Some days it never bloomed.

Kill them early and kill them often would be my suggestion. When you think of this plant, think INVASIVE, such as in “Invasion of the Body Snatchers”.

(Sorry for the SHOUTING. I am just trying to warn you.)

On Jun 25, 2004, DiOhio from Corning, OH (Zone 6a) wrote:

I love this flower. We have it wild here in SE Ohio. One year it came up in one of my flowerbeds and I’ve left it reseed year after year.

On Apr 5, 2004, nansgarden2 from Silt, CO (Zone 4a) wrote:

Bladder Hibiscus or Flower of the Hour.
Found in Asia Africa and all Australia.
Good bedding plant slightly upright trailing habit.
I purchased a single 3″ potted plant from an organic herb farm over 4 years ago . The sales lady told me it would probably only survive as an annal.This annual-biennial is very hardy, tolerates dry heat. Self sows and can become invasive if you do not remove seed pods and or new seedlings in your garden.
They are the most beautiful flower, Creamy petals with an almost black/violet center.
It will take your breath away!

On Sep 3, 2003, henkmaters2 wrote:

We bought seeds for this plant in New Zealand and it has grown over two meters high! As of September 2003, it’s still pushing and flowering.
Henk Maters

On Jul 20, 2002, lupinelover from Grove City, OH (Zone 6a) wrote:

Plant self-sows prodigously and apparently the seeds can survive in the ground for many years, waiting for the correct conditions to germinate.

Flowers only remain open for a few minutes, closing as soon as clouds or shade strike them.

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Wednesday Weed – Hibiscus

Hibiscus syriacus ‘Red Heart’ (also known as Tree Hollyhock)

Dear Readers, is it just my imagination or has there been a sudden burst of enthusiasm for hibiscus as a garden plant? Once upon a time I had to travel to the Mediterranean to see these exotic beauties in full flower, but on a wet Sunday afternoon I found no less than three different plants in the environs of the County Roads in East Finchley, and very splendid they were too. I suspect that the climate change induced warmer temperatures are suiting them very well, for this plant comes originally from southern Asia, with its long warm summers. Hibiscus arrived in the UK in the 16th century, and was at first thought to be unable to survive frost. Later, it was realised that although individual buds might be affected by sub-zero temperatures, the shrub itself was frost-hardy.

Hibiscus syriacum is part of a genus of several hundred species belonging to the mallow family, or Malvaceae. In the UK the plant is also known as the Tree Hollyhock, but in the US it is also known as Rose of Sharon, a name that in the UK refers to a bright yellow member of the St John’s wort family. Yet again, we find ourselves divided by a common language, and I give huge thanks to Linnaeus for his system of nomenclature that enables us all to understand what we’re talking about.

I love the way that hibiscus flowers open, the petals swirling around as they open like a ballerina pirouetting.

A hibiscus flower opening….(Photo One)

Many hibiscus species (mainly the red ones) are pollinated by hummingbirds or sunbirds, but our plant, originating in China, is not. It is both self-fertile (i.e. each flower contains both male and female parts) and capable of being pollinated by insects, chiefly bees, who are attracted more for the plentiful pollen than for the nectar. Each flower only opens for a day, but in a good year the shrub will be covered in blooms for weeks, providing plenty of opportunity for pollen-hungry invertebrates.

Hibiscus syriacus is the national flower of South Korea, where it is known as mugunghwa, from the word ‘mugung‘ meaning ‘eternity’ or ‘inexhaustible abundance’. In the South Korean national anthem, reference is made to ‘Three thousand ri (about 1,200 km, the length of the Korean peninsula) of splendid rivers and mountains covered with mugunghwa blossoms’. It is not surprising that Hibiscus syriacus became the national flower after Korea gained its independence from Japan in 1945.

The Emblem of the President of South Korea, showing a hibiscus blossom (Photo Two)

The leaves of Hibiscus syriacus are said to be a good substitute for lettuce, though a little mucilaginous. The buds are said to resemble okra (not necessarily a good thing in my opinion, but each to their own). The flowers are edible, although it’s the dark red flowers of Hibiscus rosa-sinensis that are more usually used to make hibiscus tea. I must admit to getting a bit irritated with the way that so many herbal fruit teas use hibiscus as their first ingredient in order to bulk it out – I find the rather astringent flavour overwhelms everything else. You can also get hibiscus syrup, again, normally made from Hibiscus rosa-sinensis. The ingredient is having something of a ‘moment’ in trendy restaurants at the moment, and to be honest I will be delighted when the moment has passed, and we can get back to normal food, like charcoal bread or aubergine icecream.

Hibiscus-Poached Rhubarb,Garden radishes,Belgian endive,ruby beet essence and toasted hazelnut ‘Génoise’ (Photo Three)

Hibiscus,parrot tulips, carnations, a rose, and iris, snowballs and other flowers in a vase on a partially draped stone ledge with a garden tiger moth by Nicolaes van Veerendael (Public Domain)

And for our poem, I rather liked this, by American poet Jim Ballowe who is, quite rightly, Artist of the Month for August 2018 at the Center for Humans and Nature website. Do have a look at his other work, too.

Remember that in North America Hibiscus syriacus is known as ‘Rose of Sharon’ and is thought to be the plant referred to in the Song of Solomon.

Lessons from the Garden

The garden doesn’t give a fig for Solomon

any more than we know what he meant when he said

that kisses are sweeter than wine. The white fly

sucking at the belly of sweet potato leaves

pauses to ponder neither sex nor text.

Remember that piece of fluff, that ancient ephemera

circling the Rose of Sharon, settling awkwardly

at last in the sun-warmed bird bath,

how determined it was to continue on the wing again

after we plucked it from its futile folly?

Think how the Rose of Sharon greets spring as a dead stick,

then revels through summer days in a pink pregnancy,

each night dropping its spent blooms

nestled like newborns curled in silk blankets.

In a month of spiders, butterflies, and hummingbirds,

in days of asters, mums, and Autumn clematis,

in sun-harsh hours cascading into velvet nights,

in lapsed minutes the sumac takes to redden,

the unexpected forever happens, and we,

thrilled to see the intricate web, the floating color,

the darting shadow, the many-petaled flower,

the diminishing light, are reassured by nature’s tricks,

the existent summer’s ephemeral exit,

fall’s hovering presence awaiting embrace,

geometrical designs in crisp skies,

the unmasking of trees, the sense of humor behind it all,

a stage whisper, the thought that we too

share this scene, waiting to go on.

Dear Readers, is it just my imagination or has there been a sudden burst of enthusiasm for hibiscus as a garden plant? Once upon a time I had to travel to the Mediterranean to see these exotic beauties in full flower, but on a wet Sunday afternoon I found no less than three different plants…