I have Sedum Autumn Joy in a bed with other perenials in full sun. They are just starting to bloom. There seem to be some kind of gnats on them. They are not on any of the other plants. 1. Will they harm it? 2. Can I get rid of them without killing the butterflies? If so, how? Thank you very much.
These are actually fungus gnats, which commonly affect these plants. This article will help: https://www.gardeningknowhow.com/special/children/fungus-gnats.htm
Neem oil will help take care of these pests and will not hurt the plants or beneficials in the garden. Here is more information: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm