I never knew hormworms ate geraniums too. Both nighshade family plants, and geraniums do seem to have a similar pungent odor that is probably associated with a chemical marker that draws the female moths in. The only thing I could think of doing is planting tomatoes, peppers and real tobacco, and hope the moths make a detour over to those plants instead of your beautuful petunias and geraniums. I think Sphinx moths are beautiful, and I much prefer relocating the catetpillars to a suitable, alternative host plant rather than cruelly ending their precious lives.

Jay, I don't think what's eating her plants are hornworms that turn into beautiful Sphinx Moths. They'll turn into ugly little tan colored moths. Tobacco budworms

I’ve tried Bt with questionable results. Now am using Spinosad to try to control them. They found their way to the window boxes, and the petunias there are now showing damage. Planters on the patio looked like they were recovering but now showing some damage again on the calibrachoa. Won’t be planting petunias or geraniums again. Ever.

I read something the other day that suggested that budworms are appearing earlier in the season than they used to and surviving winters further north than before.

I replaced some of the geraniums with Madagascar Periwinkle and removed the golden creeping Jenny run amok in the window boxes. Won’t buy that again, too spready. Planted scaevola instead. In another container area Mandevilla (Dipladenia) looks fabulous, first time for me. New Guinea Impatiens in one planter collapsed due to botrytis. Waiting on the other two planters to see if they do the same. :o( My landscape/Hort guy said he planted several hundred NG Impatiens in mass plantings for some of his clients and they’re not doing well. Bummer.

Gardenfanatic, you are right, I stand corrected. This is the first time I heard about budworms. I just assumed the topic was about hornworms, because they go by different names in different parts of the country. Saypoint, I have never encountered them in my area, but I think you are doing the right thing by switching to plants that the worms don't bother. Putting up some wren houses could help at controling the worms as would attracting wasps into your garden.