Removing magnolia tree infested with scale. How do I treat hydrangea and ferns underneath and mulch covered in honeydew? Are there
any worries in planting a new tree in the area? I read, and feel more information is needed. Do I have to worry about nearby trees, birch and maple and jewel crab? Hydrangea? In the process of removing infested tree. Plants underneath are covered in honewdew. Will hose off, but any other precautions?
This might be a difficult problem to treat. I would coat all plants that are not yet infected with neem oil so that they will remain pest free. As far as dealing with the Magnolia... Winter may kill most of them, and you can start fresh by using rosemary oil in water to water with. The tree will take this up and scale bugs will find the tree toxic to consume. If the infection does not subside this winter, then cutting the tree down may be the best option.
The sap is from the insect damage and can be washed off. All trees should be sprayed with neem oil to protect them from future infestation. I would also apply the rosemary water to these as well.