Q.Gardenia Potted Diseases/Pests
I have a common Gardenia which lives through winter in a sunroom and summer under a tree where it gets morning light. I have been fighting a pest – black, small pinhead size that collects around the buds and causes them to fall. Below the infected part will be a white tiny (eggs?) residue, again like small pinheads. Have tried Cygon, Raid, soap, Malathion, and copper but this thing keeps coming back. Can you help?

Certified GKH Gardening Expert
The following articles should be of some help to you: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-pests.htm
https://www.gardeningknowhow.com/plant-problems/pests/homemade-aphid-control-a-natural-way-to-kill-aphids.htm
https://www.gardeningknowhow.com/problems/pests/how-to-make-white-oil-for-an-insecticide.htm
You may also want to try neem oil. It is both an effective pesticide and fungicide. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm