Does anyone know anything about "mosquito plants" (aka pennyroyal)? I want to plant some in my butterfly garden to keep the skeeters out, but only if it doesn't repel butterflies as well...help?

I planted several black pennyroyals this summer, and have had no problems with butterflies keeping away. BUT since it is such a small plant, keep in mind that it is surrounded by many other flowering plants. Hope this helps.