Plant ID Needed Please?
 

This was suppose to be an Astilbe bought mail order and planted last year.
They were all on the small side of course and did not do much last
summer,but all lived.

Now this spring this one has gone crazy! Doesn't look to be an Astilbe and
must have been a mispick during shipping. It has shot up like crazy and has
thorns on the back of the stems. Almost like some kind of briar plant
thought the leaves do resemble the other plants.
Anyone know them to have thorns? Anyone ID this for me please?
TIA
Elaine in GA
(sorry the close up is fuzzy)