How to treat Magnolia with brown and eaten leaves?

Question

Hello,

I planted this teddy bear magnolia tree about 9 months ago. There are large brown spots on the leaves and holes in the leaves. I am unsure if it’s due to the heat, fungi / disease, or is being eaten?

It has been an ongoing problem. I have placed bark around the base tree (not against the trunk) to help with heat control and have also added, once, the osmocote food and soil improver for roses. I water twice a week.

Do you have any other suggestions please?

Thanks

Sarah

JacobZ · Answer

Hi @sarah1FR,

From the photos it looks like two separate issues affecting the leaves. The holes and chewed edges are typical of insects such as caterpillars or beetles feeding on the foliage. The large brown circular patches with darker edges are more consistent with a leaf spot fungus, which can develop when leaves stay damp or from water splashing up from the soil.

The good news is that both problems are fairly common on young magnolias and are usually cosmetic rather than serious. The tree itself looks healthy and should continue to grow well once the causes are managed.

A few steps that should help:

• Remove and dispose of badly affected leaves to reduce the spread of fungal spores.

• Check under leaves for caterpillars or insects, especially in the evening, and remove them if found.

• If insects persist, apply a general garden insect spray such as Eco Oil, ensuring both sides of the leaves are covered. Repeat fortnightly if necessary.

• For the spotting, a copper-based fungicide can help if the issue continues.

• Continue deep watering twice a week, ensuring you water at the base of the plant rather than over the leaves to keep foliage dry.

Your mulch placement and watering routine sound good. With a little pest control and by keeping the foliage dry where possible, the new leaves should grow through healthy, and the tree should establish well.

Check out Growing, Pruning & Caring for Magnolia for some further guidance and please let us know if you have any further questions.

Jacob