Two years ago these worms, attacked my snow ball bush, and totally stripped it. It just started blooming, and has leaves on it for the first time in two years , and noticed they are back. I have sprayed it with BUG B GONE and no effect. Can you help me, need another solution.
Thank you for contacting Toronto Master Gardeners about the defoliation of your snowball bush. The first distinction we need to make is whether the shrub is an hydrangea or a viburnum, which are each known by that common name but are different species of plant. The following document describes and illustrates the two species. https://homeguides.sfgate.com/difference-between-snowball-bush-hydrangea-52472.html
In order to determine a method of eradication of your shrub’s pest, we need to correctly identify the ‘worm’ or caterpillar that is consuming the foliage and flowers. The following document https://bugguide.net/node/view/57/bgimage?from=24 has coloured photographs by which you can determine the particular pest. At present we cannot deduce either the size or the characteristics of the pest, such as stripes, spots, fuzzy texture, smooth, with knobs, etc. by which we can attempt to identify it.
Armed with this information we will be happy to research horticultural material to find a solution.We hope to hear from you again.