|My bed of physostegia (Obedient plant) has small perfectly round "polka dot" spots on every single leaf. The spots almost look like they are part of the leaf.
The plants do not seem to be stunted, and none of the leaves have turned yellow or have fallen off. Is this a fungal problem? Or a virus?
I really don't want to remove the plants, but if I have to -- do I need to do anything to the soil before replanting?
|Your Physostegia will have spike-like clusters of lavender-white 1" tubular flowers in August, leaves 4" long at base of plant, average (moist to dry) soil, sun to part shade, spreads well, 2-3' tall. If the flowers are moved on the stem to face a different direction, they stay in the new position - hence the name 'Obedience plant'.
If the plants are vigorously growing, I wouldn't be too concerned about the dots on the leaves. Be sure to check the undersides to make sure there are no rust spores (fungal disease) that might be causing yellow dots on the surface.