I live in Zone 8a, the South Carolina upstate. After 3 years in this house with no issues, I noticed white flies in the landscaping end of last summer. I thought the problem would fix itself, but at spring pruning, I found my gardenias were almost solid black with sooty mold. Some research and a peek under the leaves confirmed white flies were the problem. So I took the following steps:

1) Spray with a stream of water. (But it seems the flies just fly around a little and come back when I've gone). I've also done vigorous shaking. On my denser bushes I even trimmed out all the interior branches and disposed of them to try to cut down on numbers.

2) Treatments with Bonide All Seasons Horticultural and Dormant Spray Oil. The directions say do it every 5 days; I probably get to it more like every two weeks. But still, it's mid-July and I've been doing this since at least early April. (Yes, I am adjusting the concentration as the seasons change, according to directions.)

3) Treat with Bonide Systemic Granules Insect Control. I thought one treatment of this would do the trick, but I am soon coming up on 8 weeks which means it's time again.

Despite all this, I'm still seeing plenty of white flies, esp on the gardenias. (Current images below.) It seems they also move around my other plants, sometimes the dahlias, sometimes the pumpkins, sometimes the hollyhock. I try to keep note of where I've seen them and spray everywhere, but it's exhausting to keep up. The sooty mold is mostly gone, but I feel if I stop treating now while I'm still seeing flies, the whole situation will just degrade again.

How long will this go on? Is there anything else I can do? Anybody out there got some white fly tricks up their sleeves? Thanks so much for your help!