I am in need of some help with a wood lily plant ( I believe that's what it is). The leaves are turning a deep purplish/brown color now that fall is hitting in Washington state. Do I cut down the entire plant to its base and mulch over it for fall or do I just let it die? It seems to me like it's completely dying as I had another smaller version of the same plant that completely died but I think it was due to the heat wave that hit us up here and I was not watering enough so I am worried this other one is going to die too and it's so beautiful HELP !!