A. Nootka Falsecypress (Chamaecyparis nootkatensis ‘Pendula”) is known to be hardy and until recently, was thought to be relatively insect and disease free. There is a fungus, Phytophthora lateralis, which rots the root system, this in turn, kills the tree. However, there could be other reasons why your tree is turning brown and dropping needles, and these should be explored before assuming the worst. Nootka Falsecypress prefers a moist, well-drained soil in a sunny area, protected from wind and if any of these conditions are not met, it may be the cause of the problem. As your tree was professionally planted, I would suggest that you contact the company that did the work. Most landscapers and garden centres offer a two-year guarantee on their plants, and would probably replace the tree when they learn of its condition.
Zone 5 Director
Master Gardeners of Ontario Inc.