Can I prune my Gardenia tree to give it better air flow? I live in Columbia, SC and it is Feb. I have tried prepared solution and homemade. The mildew would slow down production but has never gone away. I have been treating this for several years.
Here is a link to an article on pruning your Gardenia tree for you: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/when-to-prune-a-gardenia.htm
Many times the home brews are not really mixed just right to deliver the needed knock out punch to Powdery Mildew and thus it comes right back. I have found an Earth Friendly product called Green Cure to be the best product on the market for getting rid of Powdery Mildew and some other fungus related problems. Green Cure should be mixed at the cure rate listed on the label and applied at 7 to 10 day intervals for the first three sprayings. Then a spraying once a month at the Cure Rate should keep things in check unless it is real humid. Then you would need to stick with the 7 to 10 days or maybe push it out to 14 day intervals. When the weather conditions are at their optimum for PM it is very difficult to control and one must really keep after it. Do an online search for where to buy Green Cure online if it is not available locally at garden centers. I order it online from a website called Planet Natural.