Species Iris, Yellow Flag, Yellow Iris, Water Flag Iris

On May 27, 2020, Katie_M from Marshfield, MO wrote:

So my husband and I moved into our first home a few years ago. The people who lived here before us did not maintain any of the plants or trees. (Shame on them because this little spot is our paradise) We had no idea of all the plants and trees that this land had due to buying in November and they let the grass grow waist high.

The following Spring, we discovered we had two Apple trees, four Pecan trees, so many peonies, and bearded irises along with these white and yellow flag irises which I have never seen before here in SW MO.

I have not had a problem with them being invasive, so I wonder if whoever planted them years ago knew what they were doing. They have clumped up into a huge patch, but haven't spread. Looking at past comments, this may be because it... read more's in a spot that is well drained and not in a swampy/pond area.

They are a very pretty, unique flower that grows tall. I enjoy them.

On May 31, 2017, fatboyest from Cabot, AR wrote:

Perfect in central Arkansas for a ditch that hardly ever dries out completely (48" precip spread over the whole year); basically a mudhole but now filled with these big self-care plants.

On Feb 1, 2014, coriaceous from ROSLINDALE, MA wrote:

This escaped into nearby wetland before Massachusetts banned it as destructively invasive. Knowing what I do now, I would never have planted it.

Louisiana irises and Iris versicolor and I virginiana are similar in appearance, have great flowers, thrive under the same conditions, and don't threaten the environment.

This species has been prohibited or declared a noxious weed by 7 states. According to BONAP, it has naturalized in all but three of the lower 48 states.

On Jun 18, 2012, RustyThumb from Ogden, UT (Zone 5b) wrote:

This was planted by the previous owner around our fish pond. It was not until this, our third year, that it dawned on me how invasive it has become. I am tearing out huge stands of it because it's dominating and crowding out or hiding other plants I'd like to show off. Now every little start is getting ripped out. It gets down between flag stone and rocks and anchors in so well I have no choice but to just hack away, hoping to do enough damage to kill it. The top of my rock garden is choked with it and I'm going to have to dig in precarious positions to get some of it thinned out.

I was going to try to give some of it away but after reading this they are going in the garbage.

On May 29, 2011, relentless1 from La Grange Park, IL wrote:

It is a beautiful, floriferous structural plant in my garden. The conditions for keeping it controlled must be wet, heavy clay soil in zone 5 in a flood plain (at least one multi-day flood every year), that dries out and sometimes cracks in the summer. Also good: the deer around here don't eat it!

On Jan 7, 2011, bonehead from Cedarhome, WA (Zone 8b) wrote:

I have to give this a negative as well. When we first dug our pond, my aunt gave me some starts. She jokingly told me to just toss them around and not bother to actually plant them. I should have paid attention. These are impossible to get rid of and have taken over huge sections of my pond banks. I actually don't mind them and they are pretty in bloom, but I am concerned about their competition with native plants. The best I can do at this point is to keep them under control and not let them spread any further.

On Feb 18, 2010, eclayne from East Longmeadow, MA (Zone 5b) wrote:

Noxious Weed Information:
Iris pseudacorus L.

This plant is listed by the U.S. federal government or a state.

Connecticut:
yellow iris Invasive, banned
Massachusetts:
Yellow Iris Prohibited
Montana:
yellow flag iris Category 3 noxious weed
New Hampshire:
water-flag Prohibited invasive Species
Oregon:
yellow flag iris "B" designated weed
yellow flag iris Quarantine
Washington:
iris, yellow flag iris Class C noxious weed

On May 27, 2008, soivos from Annapolis, MD wrote:

Yellow Flag (Iris pseudacorus) is a non-native plant which has escaped cultivation in water gardens and has established itself in local creeks and coves. It spreads rapidly, out-competes our own native species, and is difficult to eradicate.

Please consider some of the native alternatives instead, such as:
Iris prismatica (slender blueflag)
Iris versicolor (blue flag)
Iris virginica (Virginia blue flag)

For alternatives that are not in the Iris family, refer to the US Fish & Wildlife Service's "Native Plants for Wildlife Habitat and Conservation Landscaping--Chesapeake Bay Watershed"

Orontium aquaticum (Golden Flag) is a wonderful native that offers a longer bloom season of very unique yellow and white 'flowers'
... read more /> Annapolis, Maryland, Zone 7

On May 23, 2007, WUVIE from Hulbert, OK (Zone 7a) wrote:

I won't give this plant a negative because it is wild by
nature. It is not a plant you can plunk in the garden and
expect it to keep it's elbows off the table.

As they do quite well in a pond setting, a pot is the only
way to go for those who cannot tolerate it's wild behavior.
You could even bury a pot in the ground, using screen
fabric to ensure the roots don't wander about, then you will
both be happy.

I love my Iris pseudacorus and would like to have even more.
Thank goodness hubby is digging another pond.

On Apr 16, 2006, Sherlock221 from Lancaster, KY wrote:

My experience with this plant has been positive. I bought it at a nursery about 7 years ago. I have it planted in three areas of my yard -- but they are not wet areas. I would call the moisture conditions normal in two areas and a bit on the dry side in one area. They have thrived under both conditions, but have not been invasive. They have spread, but fairly slowly and have lovely blooms that last a long time. Perhaps when grown in a drier area of the garden they are easier to contain. I live in the Bluegrass region of Kentucky.

On Apr 12, 2005, QueenB from Shepherd, TX (Zone 8b) wrote:

I didn't realize until I moved to my current location how invasive this stuff can be. There are several locations just within my rural subdivision where this plant has gotten a toe-hold in ditches and along natural run-off areas. It doesn't seem to mind full shade at all, and grows no less than 6 ft. tall in the sun! I made the mistake of planting some in my yard, which I'm more than likely going to pull up before they get out of control.

On May 3, 2004, MTkittlecat wrote:

This plant is considered a noxious weed by many states, including Montana (listed 6/03). If I could attach a photo I would show you how it has choked streams and causes channel braiding. Before planting anything please check your state's noxious weed lists. Most are available on-line. Plants are classified as noxious for good reason! You can't trust all nurseries to know what is noxious in your state; especially an on-line nursery that is not familiar with weed lists in all states (I have no particular nursery in mind but have seen a local hardware store carry yellow iris in the spring). Having said that -- I do have yellow iris in a very dry location in my yard (not near any water) and it will spread by tubers, but I have never had it spread by seed. It does not readily take over in... read more a really dry location and will still bloom.

I specialize in native plant research and restoration and have a lot of botanicals in my yard as well. I feel that anytime you plant a species you can't control because of seed spread or rhizome/suckering there is a chance that plant may become a future noxious weed. Look for a hybrid without nuisance qualities. We have several very pretty noxious weeds in Montana but they will outcompete native vegetation and wildlife food and water sources.

Please know your plant and plant safely!

On Nov 24, 2003, suncatcheracres from Old Town, FL wrote:

The species may be considered a rampant invasive, but there are some nice hybrid cultivars of this plant that will behave in the garden, although most are no longer pond plants, as they are crossed with "land" irises. 'Holden Clough,' has pretty tan flowers with red veining, and grows to four feet tall. 'Phil Edinger,' has large brassy colored flowers, with heavy brown veining, and also grows to about four feet. 'Roy Davidson,' with dark yellow flowers with finer brown veining, and a maroon signal on the falls, is also smaller. There is a pale cream variety called 'Primrose Monarch,' and a nearly white called 'Alba,' and a solid deep yellow called 'Golden Queen.' The 'Variegata' cultivar has the usual yellow flowers, but in the Spring the foilage is variegated, which fades to all green... read more in the Summer.

The species, on the other hand, can get huge, to over six feet tall, and the rhizomes are the largest of all the irises, and were used medicinally in Europe in the Middle Ages. The species does "best" in or near water, so perhaps planting it in regular, but moist, garden soil will help keep it contained. But it can stand being submerged all year round up to about USDA Zone 4, unlike the more tender Louisiana irises.

On May 25, 2003, Terry from Murfreesboro, TN (Zone 7a) wrote:

I second Baa's comment about it being unsuitable for smaller ponds. We have a mid-size pond (8x12 or so), and a pot of this (inherited with the pond) has rapidly become grossly overgrown and unwieldy, stretching 4' across, and is now almost too heavy to lift the pot out of the pond. Smaller pots of it were divided (with a machete!) and given away last year; this year may be the year we finally give up on it entirely.

The only reason I don't rate it a negative (and haven't already removed it altogether) is because it does provide a place for our fish to spawn.