Spring has barely sprung, and already plant disease has arrived. The rosemary has developed powdery mildew. It’s basically what it sounds like – a powdery white fungus that grows on the leaves of plants. It occurs most often in plants that don’t get good air circulation and are in humid, stagnant conditions. Which is why I am completely stumped as to why the rosemary has it – just a few weeks ago I pruned it, so it was getting more than enough circulation. And we don’t over water it, so who knows.
I’m trying to doctor it back to health. Since it was so warm outside today, I took it out on the back patio for some fresh air and the breeze. But that’s not enough to get rid of the fungus, so it was time for a treatment. There are apparently a lot of things you can do to treat it, including spraying the plant with diluted milk or chamomile tea, or rubbing the leaves with jojoba oil. Another method I’ve read about it spraying it down with a baking soda and water solution. Since that’s what I have on hand, it’s what I decided to try. So after the plant sat outside for a few hours, I sprayed it liberally with the baking soda solution and let it sit for a couple of hours. Then I sprayed it again, and tried to wipe down the leaves the best that I could. I then left it out to air dry for a few more hours.
It’s back inside now, isolated from my bay tree since powdery mildew can spread, and it looks okay. It’s a little wilted, likely because it was so hot out today, but no way am I going to water it. If the mildew looks like it’s still under control in the morning, I’ll give it a little drink then. Hopefully I can save the poor thing from this mystery affliction!