A plant that comes into the garden and by strength or by stealth overtakes it.
A plant that behaves badly.
Often it is invited in by the owner who thinks it is a charming addition and then wrecks havoc. It may spread by underground stolon or overground runners. It often seeds and seeds to an extent that you can not keep up with popping up everywhere you do not want it. Some plants can spread by more than one means.
It also can come in as an uninvited guest sneaking in in the soil as a seed or tiny piece of root. Birds can drop uninvited guests or even rodents who leave a stash of seeds.
It comes in all forms, annual, perennial, shrub or tree.
Often these plants become such bullies that they can end up on lists of noxious(weeds) plants and can not be bought at garden stores or brought legally into areas where they have tried to take over.
A Weed in deed....
Goutweed or Bishop's Weed or Ground Elder
