Answer: I really can't tell without looking at the mass under a microscope, but I suspect that either an insect or a spider is laying eggs and protecting them with webbing. Spraying insecticide probably won't work because the product would have to penetrate the mass to get to the eggs. You can handpick the masses and destroy them, or wait until the critters hatch and the webbing weathers away. Or, for a positive identification, take a few samples to your local Cooperative Extension office. (Santa Clara Cooperative Extension 408-299-2635) Knowledgeable folks there can help you find a way to deal with the problem. Best wishes with your gardenias!
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