Q.All leaves dropping off Chinese Pistache tree at early Autumn
My 3 metre high tree is in full Sun most of the day here in Canberra, on a slight slope for good drainage, and planted amongst some native correas and grevillea. It has dense green leaf cover through Summer; come Autumn the leaves begin to turn a dark mauve colour but then all fall off wthin a couple of days. No orange or yellow but a couple of streets away several similar trees are in brilliant Autumn leaf colour. What might be wrong with mine please?
Chinese pistache is a deciduous tree, so it is normal for it to go dormant and lose it's leaves as the autumn days shorten and the nights get cold. I don't know your climate there in Canberra, or when dormancy should be expected for Ch pistache, but if you think it's too early, consider premature leaf drop due to extreme water deficit/drought stress, or other physiological stress on the tree.
https://www.gardeningknowhow.com/ornamental/trees/chinese-pistache/growing-chinese-pistache-tree.htm
