A month ago I purchased a lush vibratent palm however I am now finding some of the lower fronds are turning brown and dieing. As well the tips are beginning to turn brown on the larger leaves. The first palm I had got infected with spider mites which I erradicated with a spray provided by the garden centre however the plant dried up and died. What can I do to prevent this? As well the instructions I received with my palm recommend cutting off old or yellowed fronds. How close to the trunk do I cut?