We have a Hibiscus tree that has had a powdery fungus we thought we had gotten rid of (took a looong time) but has come back. Should I get rid of it? Can it go outside? (Sun, shade, a little of both?) Will it harm the other inside plants (it hasn’t seemed to so far)?
Generally powdery mildew is specific to a variety…a different strain of mildew for each variety. This is probably why it hasnn’t spread. It would enjoy being outside but first to a bright but shady area and gradually to brighter and brighter location as it adjusts to sunlight. Expect it to lose leaves in the process. Spraying with neem oil will help control the mildew.as will occasionally misting of the leaves.