Hi, trying to figure out what’s wrong with this blue Palm, which is supposed to be resistant to most Palm disease. Lower fronds are dying and there is discoloration in the stems prior- see photos- a type of fungus, or too much water or too little? We live in hot inland Southern California. We deep water on average twice a month. West-facing but has a high hedge on the south side so sun varies from full sun in summer to part sun in winter. Help?