Troubleshooting
Southern Magnolia problems — and how to fix them
Southern Magnolia (Magnolia grandiflora) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Chlorosis (yellowing leaves)
Iron and magnesium lock-out in alkaline soil. Lower pH with elemental sulphur or chelated iron and mulch with acidic organic matter.
Leaf drop and litter
Evergreen leaves are shed gradually year-round, heaviest in spring. This is normal, not disease; the leathery leaves break down slowly, so rake to keep the bed tidy.
Scale and sooty mould
Magnolia scale excretes honeydew that blackens leaves with sooty mould. Treat with horticultural oil at the crawler stage in late summer.
Slow establishment
Transplant shock is common; the coarse, fleshy roots resent disturbance. Plant in spring, water consistently, and avoid moving an established tree.
Prevent southern magnolia problems before they start
Most southern magnolia issues are care-mismatch, not bad luck. Dial in the basics:
Southern Magnolia problems — FAQ
Why is my southern magnolia chlorosis (yellowing leaves)?
Iron and magnesium lock-out in alkaline soil. Lower pH with elemental sulphur or chelated iron and mulch with acidic organic matter.
Why is my southern magnolia leaf drop and litter?
Evergreen leaves are shed gradually year-round, heaviest in spring. This is normal, not disease; the leathery leaves break down slowly, so rake to keep the bed tidy.
Why is my southern magnolia scale and sooty mould?
Magnolia scale excretes honeydew that blackens leaves with sooty mould. Treat with horticultural oil at the crawler stage in late summer.
Why is my southern magnolia slow establishment?
Transplant shock is common; the coarse, fleshy roots resent disturbance. Plant in spring, water consistently, and avoid moving an established tree.