What is this plant?

[Steiner]

Customer asked me how to deal with the care of this plant. Problem is I have never seen it during the spring summer so I am at a loss as to what it is. Can you help? I am in zone 4A in Central NY.

[Twitchy]

It looks like selinum wallichianum aka Himalayan parsley. Its a wild flower perennial. Get rid of it. It's junk.

[AGLA]

It looks like some type of yarrow to me (Achillea spp.).

[Isobel]

looks like Achillea millefolium, aka Yarrow.

deadhead through the year. Looks large enough that you could probably divide it if the client wants it smaller.

[Lite4]

Looks like Yarrow to me too

[Steiner]

Thanks guys! Always appreciate your help!

[EagleLandscape]

It is Yarrow.
Just cut off the dead shoots. and it will more than likely freeze back to the ground when the cold winter comes.