I have oregano and they sow themselves everywhere! So if you don't want that, I would suggest to plant these just in containers. I don't know about thyme.
Mae

In my zone, I have never had thyme or oregano reseed themselves. I do grow them in the veg garden and not the flower beds, so perhaps it's because I turn over the whole veg garden each spring.

You might have better luck getting info about invasive plants in OK if you post this to the Oklahoma Gardening Forum. Which is probably what you meant to do...

As for mint, I have battled it before, and it took years to get it all up (I didn't plant it in the ground myself- I inherited it). I love it, but I only grow it in containers, and I keep an eye on the containers to be sure the sneaky devils aren't sneaking out the pots through the drainage holes.

My understanding is that oregano tends to prefer being grown in pots- though that could be a local thing, and not applicable to your area...

Good luck,
Virginia

I have oregano and thyme in zone 9b California and they are NOT invasive here. Nor have I ever heard of them being invasive. They are wonderful herbs to grow and I have lemon thyme among my roses that has spread to a nice ground cover. My oregano has never reseeded although I've given it plenty of chances to! Also, look at terragon which is very pretty as well as tasty. It grows back here in spring but might be an annual in OK.

Anne

I wonder if there are levels of invasiveness as in invasive and bad and invasive and beneficial.

What could possible make an invasive beneficial? I can think of at least two things.

One would be shallow rooted....and keeps other weeds from growing.
Two would be harbors beneficial insects.

I'm currently battling Creeping Charlie. I'm not sure if its' good or bad, but I'm leaning to think that it may be good.

It is a ground cover that's low growing (good)
Very few bigger, more water hungry and much more vigorous weeds seem able to germinate where CC is established (good)
It's a mint and a lot of mints are good beneficial hosts. (unsure if the bene population on this is going to happen. Will start checking with a microscope midsummer).
It protected some new growth during our very late last freeze. (Good.)

Don't know if I can get rid of it even if I want to.

Comments welcome.

Lilly turf (Liriope) is the worst for me I can't ever get rid of it.
I had Houttuynia spread into my plot from another gardeners area it's also an invasive. Morning glories. yech.
Amaranth (love lies bleeding)
Cleome is pretty but 2 plants 1 years produce 12 the next

I am a huge fan of thyme; I must have 20 different kinds around, at least. There are two basic types. Some (e.g. Thymus vulgaris, T. mastichinus, T. capitatus) tend to form discreet little shrubs and don't run around. I get seedlings only rarely from those. Others are rhizomatous, creeping ground covers that will wander far and wide, as far as you let them, even to the point of climbing up shrubs (e.g., T. pseudolanuginosus varieties, T. thracicus, T. serpyllum). I also find seedlings of those from time to time.

I also grow lots of kinds of oregano. Greek oregano does seed around and run a bit at the root, but not too badly. O. rotundifolium 'Kent Beauty' expands very slowly and I've never seen a seedling. The rest are somewhere in between these two. The only one I have banished because of over-the-top number of seedings and root-aggressiveness is Hopley's (Origanum laevigatum). The nice thing about oregano is that it is very drought tolerant and happy with whatever incidental water it happens to get and growing it on the dry side keeps it both healthy and less aggressive, I think.

This post was edited by catspa on Thu, Jun 12, 14 at 13:01

I have purple oregano which reseeds all over the gravel path, but I really like the look of that. Other oreganos and thyme I have no problem with, in fact I struggle to keep thyme going here.

I agree about houttuynia, and also perennial ageratum. Both harder to pull out than mint in my experience.

The king of aggressive, invasive and hard to kill is trumpet vine -- too bad because it really can be beautiful and definitely attracts hummingbirds.

I have oregano that has spread, but not seeded. it's keeping a spot covered until I can plant roses there :) But it's not as bad as mint.

I usually plant that kind of plant in a pot. In case some seeds get out and grow, I will eventually learn to recognize the seedling, and either pull it out when young or maybe let it grow a bit and actually pull up the entire plant when needing to eat it.

My thyme and oregano may spread a bit, but they are not invasive at all -- and I wind up replacing them every few years anyway due to either drought or severe cold. There is creeping thyme which will spread and it used to fill in rock paths but I don't have any of that.

Mint and pineapple sage are the herbs I've had issues with spreading. I only grow mint in pots now. My bay laurel sends up shoots, but it doesn't seem to spread too far.

The things I have issue with are morning glories and wild strawberries that seem to be spread by the birds dropping seeds (though the strawberries are kind of neat and I may use them to fill in between the rocks in my path), fig ivy that either my PO or the neighbor's PO planted (we both blame the other, but they had tree size plants bearing fruit on their side of the fence -- that stuff should be outlawed) and some wild vines.

The varieties of oregano, marjoram and thyme I've grown spread a little but are not invasive in my garden. Easy enough to dig up and get rid out where you don't want it.

Mint is one of the worst to grow outside of a pot, including some of its varieties such as ginger mint. Onion and garlic chives are also very invasive as they seed all over. Lemon balm has also become invasive in my garden, seeds all over the place and I cannot get rid of it even when I think I've pulled up every last plant. Feverfew is also a little too self-sowing for my liking although I wouldn't technically call it invasive.

Here are some other plants that are invasive that I've mistakenly grown, many still haunt me -- vinca minor, violas (wild violets), hedera helix (English ivy, though I did get rid of that eventually it wasn't as bad as the periwinkle), lily-of-the-valley, ajuga (bugle), bishop's weed (I did not plant this but birds spread it), wild spotted geranium (I love these but have more than I wanted), black-eyed Susan, and nandina (heavenly bamboo, haven't tried to get rid of it but has spread alarmingly).