Thanks for the help folks. I thought everyone was ignoring me but turns out, there's something wrong w my email.  I only just now found the replies online.

From: "Christopher P. Lindsey" <1002@rewrite.hort.net>
To: perennials@hort.net
Sent: Monday, June 30, 2014 1:07:15 PM
Subject: Re: Zizia
----- Original Message -----
>
> Anyone growing Zizia? I have Z aptera and Z aurea, both of which have
> grown big and fat in just a couple of years. I want to divide them
> but would like to know the best time to do this. Anyone know?
>
> I did check the internet with divide, division, propagate Zizia â no
> luck. The most I found was âstart from seed but also can be
> dividedâ. So I checked my big, fat, heavy AHS book which always
> tells you when to propagate. Amazingly, this genus isnât even in
> there! I was sure it was a NAm native so I pulled out my old Hortus
> Third and yes, it is. So why would AHS ignore it? The black
> swallowtail larvae certainly didnât ignore it last year. Mobot
> covers them. Harumph!
Hi Kitty,
I don't grow these (although I'm familiar with them).  I'm not sure
why they never found a home in my garden, though.
Barry Glick says those two plants are 'idiot-proof' and readily
propagated by either seed or division; some other random links online
said that spring or fall were both equally suitable for Zizia.
I don't know if that helps or not.  :D
Chris
---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE PERENNIALS