Per the manufactureer of Maggies Farm Wasp & Hornet Killer, “Some plants/foliage can be sensitive to plant oils (especially tender new growth and blooms).  We recommend that our outdoor spray products be tested on plants/foliage to be sprayed to ensure they are not sensitive to the plant oil active ingredients. It is important to also remember that other conditions could make plants more susceptible as well, such as if a plant is stressed due to drought conditions, etc.”