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Discolored leaves - Mexican Petunia
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Date Posted: Tue, Aug 27 - 11:07 pm
- My dad has a lot of mexican petunia at our beach house in North Carolina. They have developed this odd discoloration on the leaves (see pic below). They reside in predominantly shade and have been there forever. Any idea what this could be and how to fix it? I have them here in Richmond but mine have not done that.
- First - please let me apologize for the delay in getting a response over to you! The website had some updates done that unintentionally prevented our access to answer questions! We finally have it fixed and are back up and running. We appreciate your patience! This seems most likely to be gall mites. Wet and humid conditions which are typically prevalent throughout the month of August will facilitate the growth of gall mites. Mexican Petunias tend to prefer full sun, so being in the shade has probably exacerbated the problem. From what we have read, a horticultural oil like All-Seasons Oil Spray will get rid of these mites, although they should be used with caution as they can cause phytotoxicity at high temperatures. If you are interested in reading more about gall mites here is an informative article: https://blogs.ifas.ufl.edu/monroeco/2022/08/30/what-is-this-gall-mites/ As Master Gardeners, we would also be remiss not to mention that concerns for mexican petunia to be invasive. It is currently classified as highly invasive in Florida and we imagine other states will start listing it as such as well. It spreads via both numerous seeds and lateral roots and therefor can be difficult to control and/or remove. It could be a good time to consider removing this plant and replacing it with native options. Here are a few ideas that you could think about if you are looking to keep some color in the area: East coast dune sunflower, Helianthus debilis subsp. debilis, blue porterweed, Stachytarpheta jamaicensis, tickseed, Coreopsis leavenworthii, tropical sage, Salvia coccinea, or firecracker plant, Russelia equisetiformis can be used.