I purchased very small 6 inch plants of heather last year at aldis. It did okay, and was slow to green up this spring, but I fed it with osmocote and it greened up beautifully. I have four petunia plants next to it and water them religiously, and now the heather's tips are turning brown. (pretty bad) Are they getting too much water? They are in full sun for most of the day. I backed off the water a week ago, but I really don't know anything about heather and could really use some help. I don't want to loose them. They are planted in a raised bed at the base of a royal star magnolia tree. Thanks!