I have no idea if this is an option or not, but I'd say, after you remove everything you want to keep, spray the entire area with Weed killer, the stuff that kills everything, keep watching for signs of life over the summer and keep spraying unti the fall,then sow grass seed.....I think!! I have no idea.

Hi Msscarlet,
Three years ago, I pulled them out in my garden, and planted grass seed. The grass seed germinated fine, and since the area is mowed regularly there is no sign of Obedient plant. I replant all my native thugs, in our township park(with permission). There is plenty of room for them to spread, and everyone can enjoy them.

I had two diffrent Obedient Plants in my main garden. But I have dug them out over the last two springs. Im still digging up parts of it, but im always vigilant about it and pull the roots out before they can do much more spreading. Some of that week killer stuff is really potent and keeps vegitation away for a long time, so you may not be able to plant anything in the area for awhile. How about putting some tarp or weed barrier down? You could hold it in place with rocks and put bark or grass clippings on top. You could even nestle some potted plants in the mulch to get some visual appeal out of the area. Good luck to you!
CMK

Thanks for the responses! I had considered rotatilling the area once the plants were removed but a friend of mine said that is the worst thing I can do...

I do want to put grass in there this year so I want to be careful with any chemicals. I also have a German Shepherd puppy who likes to eat dirt...

I do like the idea of putting a tarp down for a bit and frying those roots lol...The puppy might shred it to heck but it is worth a try. I would like to plant the grass seeds late summer/early fall.

CMK I hear you on digging these things up every year. I swear they are the plant from hell in my growing conditions. I also planted two varities...Miss Manners I managed to pull out and get rid of quickly, it is the other one that has spread like a rash!

Herblady, that is nice that you were able to "donate" your monsters to the park. Given lots of room they will have a ball and are pretty to look at...not so when they take over a bed though :( I KNEW they had this ability but nothing in my yard ever spreads or becomes invasive except this and Joe Pye Weed which I am also planning to pull this year. That is a toughie, the roots are like steel!

Yikes! I WSd a bunch of seed and somehow I think Physostegia was in there.... I guess I should reconsider planting it out? Is Miss Manners any better than the regular?

LIme

"You know what to do with Disobedient plants?
Give them a damn good thrashing.
(Tip)Can I suggest boiling water tipped out in a controlled fashion from a Kettle/Watering can.try it first on a single individual do not tip it over the foliage aim for the base of the stem or if the stem is hollow cut the stem at ground level and tip the boiling water down the stem tube.
No roots I have come across has yet have survive this.
It sounds harsh and can be a right Par-larva but it works.
Give it a go let me know how you get on.Dependingh how you eek it out one kettle can effectively clear a decent patch. Top the plants first at ground level and check out the stem.

Lime, Miss Manners was not as invasive as the other but still it spreads quite a bit and I have it in different places all over the left side of my garden bed. I only planted one plant in the back. It is here and there not over infested like the other one.

To be honest with you, I am so tired of it that I don't want to see ANY OP ever again lol...I learned my lesson, if something is said to be invasive, it IS...I did not think it would be because nothing in my garden gets out of control spreading wildly... just OP. NEVER ever again!

Lupin thanks for the tip on the boiling water. I am going to try it not only on the OP but the Joe Pye Weed I have as well. That stuff is soooooooo hard to dig up!

Wow - I had no idea!! My op grew into lovely drifts, but the Bee Balm and mint cornered it. I just dug chunks out every spring and took them to the Hort sale in the village. Maybe it's because I am a Zone more north, but also, vigilence with a Spade!!!

Cheers.

Omg I hate the obedient plant. I am battling it today. I have dug it up and am removing any trace of white runner I can find. I may spray it with weed killer too. I think it may have arrived at its name because it does what it is supposed to do- grow! It is awful. We also have gooseneck loosestrife in another mulching bed that is almost as bad.

I love obedient plants and even have people pull up & ask what they are. I share them with friends & they love them. Butterflies $ hummingbirds love them. I’ll take all you have! Salisbury maryland