|1) The seemingly healthy green leaves (no yellow veins or indications of pests) on my Nagami kumquat tree are falling off for no apparent reason. What could this be?
2) I have three mature fruiting olive trees. One half of one is losing leaves and becoming pretty bare while the other half seems fine and the other two are healthy. What's happening?
|Lots of conditions will cause leaves to drop from a kumquat tree. It could be a reaction to heat stress, too much or too little water, or, if the leaves are on the inner most parts of the branches, leaf drop can be a normal shedding of older leaves. As long as your tree is putting out new growth and looks otherwise healthy, a few shedding leaves shouldn't cause too much alarm.
I'm not so positive about your olive tree. Generally when only half of a tree's canopy is affected, it points to a problem with the roots. Root rot can cause these symptoms and it's just a matter of time before the entire tree is affected. If you've dug down to inspect the roots and everything seems fine, do a careful inspection of the trunk and branches of the affected part of the tree. You may find insect or disease problems. Best wishes with your landscape!