Meadow, I have had the same experience with mums. I have (only) thought about planting them, and then surrounding them with some sort of a border, (brick, cut landscape timbers, or even just some boards on their sides) to corral them, and then just pull out any that escape.

One invasive that comes to mind is Oenothera speciosa-showy primrose (pink). I planted one little plant years ago in a bed with some shrubs. It has since spread to cover about 12 square feet. It choked out a fairly good sized established Blue Star Juniper. I have pulled it, and even used Round Up on it some. It just keeps coming back. It is a nice little plant, if given it absolutely 'own' space, as there is no way to corral it. It would be pretty in a bed all by itself, or on a slope that just needed something.

I'm sure I can think of others...besides the introduced (long ago) things that have taken over here.

Trumpet Vine, though a native, and nice in the right place (all by itself) on a structure, can sure be invasive also.

Sue

Hi Meadow!

I should be so lucky. Up here in Ohio, it's a hit or a miss (more misses than hits) as to whether or not the mums will come back at all the next year. At least, that's what the people tell me from the local nurseries (and my own experience). I have one that is persistent and spreading, but that's 1 out of probably 30 I've planted for Fall foliage in the past 7 years. Doesn't matter when I plant them, how much I mulch, or how well I treat them for winter...nobody comes back...except that one.

Lol! Mums are hard to keep alive up here. Still there should be a warning that the plant may be invasive.
Remy

Invasives that I have had the un-pleasure of experiencing...

Primrose yellow
Gooseneck loostrife (very invasive)
Obedient plant that's not so obedient!!
Jerusalem artichoke- got this one in a trade and should have done my homework!
Campanula
Agastache- got this last year and it already is all over, but I like this one at least!!
Monarda- but wouldn't be without it for the hummers.

I treat my mums as annuals but I don't think they would be invasive here either...