Q: I have 2 gardenias that are covered in black soot. I have seen tiny little white bugs flying around them (I assume these are white flies?) I would like to clear up the white fly/soot problem, as well as relocate these two plants. Each is about 4ft. tall and 5ft wide. I live in Lexington, SC, and our soil is quite sandy. Any advice you can offer would be appreciated. And I just loved your column in Southern Living and am so glad I found your blog! - Candy Hayes Lexington, SC
A: Dear Candy, Aren't you sweet? (OK, I'm sorry about the bad pun. I won't do that again.) White flies are the main culprit here. They suck juices from the gardenia foliage and then secrete a sticky honeydew upon which the sooty mold grows. Get rid of the white flies and the sooty mold goes too. Ah, but it isn't that easy (naturally). White flies are very difficult to control and eradicate, because they multiply faster than Dustin Hoffman in "Rain Man." My advice is to treat your gardenias with a systemic insecticide that the leaves will absorb and pass on to the white flies. Spray the plants according to label directions with a chemical called acephate, which you'll find in several pest products, such as Orthene. You'll have to spray several times at two-week intervals. Be prepared -- the stuff smells bad. But so do husbands early in the morning.
You might also consider applying a systemic insecticide that's absorbed through the roots, such as disulfoton. It's often included in insecticide-fertilizer combo products like Bayer Rose & Flower Care. Again, follow label directions. -Grumpy