Certified GKH Gardening Expert
It is true that hibiscus can be sensitive to oil applications. I think this applies to all oils, not just neem. Because of this, you may want to dilute the neem oil by mixing it with water and a bit of dish soap, or choose a product where it's already diluted. Then, test the neem oil mixture on a small area of the plant, wait a few days, and if there's no damage you can spray the whole plant.