Another possible cause is an invasion by an insect called a thrip.

In spring the Southern magnolia drops its oldest leaves as new growth begins. Older,"tired" leaves suddenly turn yellow, throughout the tree, and those are the leaves that will be shed. They don't drop all at once, either, falling over time.

Leaves are large, each measuring up to 10 inches long, and very tough, taking time to decompose.

Jul 13, Magnolias are notorious for leaf drop just before flowering. It is especially noticeable on evergreen trees that produce large leaves and create a mess when numerous leaves appear to drop at one time. This is not something you need to worry about since the tree will put out new leaves once the flowering process has bushmulching.barted Reading Time: 1 min. Sep 21, Touch the branches of trees in which leaves are falling. Cankers and scabs are caused when fungus grows between the magnolia's trunk and the bark.

Apr 12, Some species of magnolia drop their leaves naturally during certain times of the year, particularly in the spring. It is also possible that a fungus is growing on the leaves. The color of the leaves that fall from the tree is an easy way to determine whether the leaf Estimated Reading Time: 1 min. Jul 06, Magnolia tree dropping leaves dramatically # Asked July 05,PM EDT. I have two beautiful old magnolia trees on my property and one of them is dropping leaves to an alarming degree.

I've been deep watering the tree (1/2 hour to an hour) once a week for about a month, so I don't think it needs water. A neighbor suggested that it.