Answer: Magnolia flowers bruise easily and can turn brown quickly. They also begin to turn brown as they age. The only other cause is feeding by thrips. These insect pests can damage the petals before the flower buds even open. There are several chemical controls you can try: Insectidical Soap, Bayer Advanced Tree & Shrub Insect Control, Bonide Eight Liquid, Hi-Yield Indoor/Outdoor Broad Use Insecticide and Spectracide Triazicide Once & Done Insect Killer are all registered for use on ornamentals against thrips. Best wishes with your magnolia.
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