I'm not a plant expert either! I suspect you're right that it is probably a different plant that just looks similar. If mine comes back again this year, I'll try to remember to post a pic.
Here's a pic of the marginal I have. Usually, a lot more flowers than this but it is starting the process of going to seed. You can see the immature seed pods (resemble small pea pods) hanging everywhere.
I suspect you're right that it is probably a different plant that just looks similar. If mine comes back again this year, I'll try to remember to post a pic. 
![[Linked Image]](http://forums.pondboss.com/ubbthreads.php?ubb=download&Number=11852&filename=I_subscribe_zps2qlyoyn2.gif)
