Apologies if this is mentioned elsewhere - but Red Iris flowers are there for the picking in Dalada Uplands (Charr territory).
Also theres a nice twist - you can battle a siege devourer then ride on it - similar to wurm in nightfall, but only you, not your whole party - tis fun for kicking the crap outta Charr
if you talk to gwen with one you get the quest Fire and Pain, which has a Rose Focus as reward (req 9 fast casting, +12 nrg, +30 health) no idea what it looks like as I haven't done the quest yet.