Impatiens glandulifera, sometimes referred to as policeman's helmet or Himalayan balsam. Is considered a noxious weed in 45 states, so you might want to reconsider its inclusion in your garden :-) Characterized by its ability to shoot its seed capsules over a great distance.

Oh darn Gardengal...And I thought it was so pretty :(
I guess I had best yank it and put it in a garbage bag. It seems like such a shame .... but I don't want it shooting seeds all over my lawn and garden.
Thanks for the info.

You can just deadhead the flower stalks before it even goes to seed. I'm growing some in my garden for the first time this year and that's what I plan on doing.

Tracy

YES!!! That's what I'll do too.
It is so pretty and tropical looking that I would hate to destroy it...seems so wrong somehow :)
I wonder if I could transplant it to another part of my garden ?
It is kind of hiding a beautiful rose that is trying to grow behind it.
I have no idea where it came from..and I have not even seen one before .
It must have been in a bird dropping or some thing strange like that.

The fact that it appeared spontaneously in your garden should give you some clue to its vigor. It is not disbursed through bird droppings - seeds are propelled upto 20 feet, so most likely accompanied another plant into the garden, or tracked in there yourself. Seeds are also transported by water (streams, runoff, etc.) and can remain viable for 18 months.

Again, I'd caution against allowing it to remain. Many exotic invasives offer attractive flowers or other features - that doesn't lessen their impact on the environment nor does it reduce our responsibility to keep these plants in check. It is a weed, plain and simple, and an extremely aggressive one at that. There is no shortage of other, non-invasive flowers to include in our gardens - why elect to keep something that has a dangerous invasive potential?

Yes, it's pretty and quite interesting BUT I'm with gardengal on this one. Years ago, before the internet, this plant appeared in my garden. How I wish I knew then what I know now. It won't be interesting for long and will turn into a plant from hell.
Please, Cottage Gardeners, heed this warning.

Libby

ps..........it also stinks to high heaven