How big of an area are you talking about?

Proper turf management is important for biennial broadleaf weed control. Maintain a dense, actively growing turf through proper mowing, fertilizing, and watering practices. Mow at the proper height for your selected adapted turfgrass. Coring and traffic control reduce compaction and encourage desirable turfgrass competition. It is best to control this biennial broadleaf weed in spring or fall, if actively growing at these times.

Chemical control of such weed is by using Manor (metsulfuron), Plateau (imazapic), and Spotlight (fluroxypyr) will control this winter annual or biennial weed.

I doubt someone going by the handle "organic kitten" is looking for names of poisonous chemicals.

A patch of nothing but this could be smothered with newspaper or cardboard. In the lawn, mowing should prevent it from making seeds. In a flower bed, if tangled into desirable plants, it may be necessary to remove the desired plants, smother/pull/dig the EPR, then replant. Not sure what kitten is dealing with.

I am dealing with the things in an iris bed of all things. I am pulling as fast as I can, but very time I think I have it all, I wind up seeing the stinking thing has evaded me by sneaking its tendrils around and underground. My iris bed is fairly large, but the weed is pretty much limited to one half of it. I am quite concerned, because it has escaped the iris bed and begun to encroach on some daylilies.

Thanks so much, both of you.
kay

Tendrils? Escaped? I don't think you're dealing with evening primrose, if you can post a picture someone can identify it.

Here is a picture of it last year when it has come into the roses. I think it is actually called Texas Evening Primrose. A very invasive uninvited guest in my garden.

kay

I had planted Mexican evening primrose, Oenothera berlandieri âÂÂSiskiyouâ that looks very similar. My perennial area is bare soil, but cultivated (vs. mulched). That stuff went crazy! But, I noticed that it wouldn't invade the adjacent fescue turf or a small adjacent area that WAS mulched. My suggestion is to apply a good 3" or so of mulch and see if the "invasion" decreases. I gradually hoed the primrose out completely, never giving it a chance to bloom before seedling removal. Pretty while in bloom but truly a PITA.
hortster

Horster,
Thanks so much! I have noticed that the areas I have thickly mulched don't seem to be hosting so much of this spreader. I will have to dig up the iris where it has invaded rather thickly in order to kill it, but it is time to do that anyway, so I will do so after bloom, them mulch the dickens out of the area. I am continuing to pull it up as I find it in an effort to keep it from profiting from photosynthesis.
kay

Thanks for posting the pic Kay, when you wrote Evening Primrose I just automatically thought Oenothera biennis and just completely forgot about the myriad other weedy species in this genus. I battled O. missouriensis briefly many years ago, beautiful flowers but I could tell right away what an agressive thug it wanted to be so I took it out the first autumn. The next spring it came back like I hadn't even touched it! There was a Euphorbia right beside it which was also trying to take over the world, I ended up demolishing that part of the garden and digging about a foot down to get out all of the roots, then digging both of them out whenever they sprouted back up. That pretty much finished off the Oenothera.

Oh yeah, the Euphorbia still pops up from time to time.

Jeanne, to be truthful I thought I had killed it five years ago when it first came to live here. Like you, I dug up the entire area and pulled out myriad roots etc. Then planted iris.

I am paying for last year when I did very little gardening, so it is at least triple this year. I found it in a new area, and so have been weeding this morning which will be followed by Preen (fat chance that will help) and deep mulch which will help.

Since you are still battling it, I know it will be around for a long long time.

I had a battle with passion flower a few years ago, which hasn't shown up since. That was a job, but at least you can find all of the roots, not like this one.

Thanks you for the help and the info.
Kay