Hi Jai,
" ...are there any large, white, varieties I should look into? "
Cut flower growers would probably say Benary's Giant White.
http://www.johnnyseeds.com/flo...
The heirloom zinnia variety Polar Bear is an alternative.
http://www.edenbrothers.com/st...
" ...what is the largest, darkest, purple variety that's readily available? "
There aren't any super dark purple zinnia varieties that I know of, and there should be, because zinnias are capable of really dark purples. The Benary's Giant Purple is what I would call a medium purple.
http://www.johnnyseeds.com/flo...
Benary's Giant Wine may actually be a bit darker.
http://www.johnnyseeds.com/flo...
Zinnia Purple Prince is what I would call a medium purple.
http://www.edenbrothers.com/st...
And zinnia Giant Cactus Purple is also just "medium" in my opinion.
http://www.hazzardsgreenhouse....
Zinnia Gigantica Cherry is unfortunately not "Black Cherry"
http://www.hazzardsgreenhouse....
I have had zinnias a little darker than medium purple, but nothing approaching dark purple. The Haageanas can do dark purple.
We need to get that dark purple transferred into a large flowered zinnia.
ZM (not associated with any product or vendor mentioned or linked)
