Submitted 07/04/08 11:17:09 by Frances Campbell from Charlotte.

Q Another gardenia question!! I have two large gardenias which bloomed profusely this summer. For the second year in a row, they are infested with white flies. I've used horticultural oil, but getting to the undersides of the leaves on a large plant is difficult, and the directions emphasize that. I have just given them a drastic pruning since they were getting to large for the space, and I will spray them well. Should I remove and replace the mulch around them? Is there anything other than horticultural oil for this pest? I love the flowers, but hate the white flies!! Many thanks and I love your column. Frances Campbell

Answered 07/18/08 23:03:41 by Nancy Brachey

A: There are systemic insecticides that the plant's system absorbs and kills the insect as it feeds on the plant. Check labels and make sure white flies are listed as a target insect for the product. I do not think it is necessary to change the mulch for this problem.