Q.Can I fertilize my Dogwood tree in Sept.
My red flowering Dogwood tree is losing leaves and many of its small branches are dead. Leaves are small. The soil lacks nitrogen. I planted it three years ago, and it did well the first year. Can I fertilize it in Sept. and can I use holly fertilizer?
Did you do a soil test?
If your soil needs amending and is lacking Nitrogen, you may want to top dress with some good organic material.
Compost is a great way to do this.
I'm listing a few links to refresh you on the care of your Dogwood.
Generally the only fertilizer that would be needed would be a light slow release fertilizer. I would recommend that application in the spring.
To much Nitrogen will actually cause fewer flowers.
Check watering and inspect for insects or fungus issues.
https://www.gardeningknowhow.com/ornamental/trees/dogwood/caring-dogwood-trees.htm
https://www.gardeningknowhow.com/ornamental/trees/dogwood/dogwood-tree-not-flowering.htm
https://www.gardeningknowhow.com/ornamental/trees/dogwood/fertilizing-dogwood-trees.htm