Monroe Chat

Given all the rain we've been getting, powdery mildew is likely to rear its ugly head.

I have a new Physocarpus opulifolius 'Mindia' (Coppertina TM) that is covered in it. What to do?

The real bummer about fungi (and powdery mildew is just one of many) is that there really isn't an effective cure. Once a plant has a fungal infection, it's there. The best way to "get rid" of it means removing the plant parts disfigured by it.

Don't get me wrong, though. There are several fungicidal preparations available, but they generally are nasty players with both the environment and the applicator.

The best cure is prevention.

First off, try to avoid plants that are susceptible to powdery mildew. This isn't always easy. Take tall garden phlox (Phlox paniculata) for example. There are a few cultivars that are resistant, but none that are immune. So when conditions favor the development of powdery mildew, even those may end up getting some mildew. Same goes with any other plants that tend to get the disease (bee balm [Monarda], lilacs [Syringa], many plants in the rose family [species of Rosa, Malus, Physocarpus,...], and so on.

If you already have plants that tend to get mildew, use good cultural practices to minimize the occurrence of mildew on the plants:
-trim out infected parts (the usual recommendation is to burn that, but I just chuck it. don't compost it; that keeps the spores around)
-avoid wetting the plant
-if you feel you have to wet the plant, do so in the morning so the leaves dry sooner (as opposed to in the evening, when the leaves will stay wet longer)
-don't fertilize excessively (especially with a high nitrogen fertilizer) as this will result in lots of new growth that tends to be more susceptible to mildew

As for my Coppertina TM, I'm going to trim it back and make sure it gets planted in a very sunny spot.

So we have a Fungus Amongst Us?

I actually do recall having this issue. Honestly couldn't tell you what plants I had in the ground at that time... but was astonished when I kept finding little patches of what appeared to be 'black dust'

All joking aside, I would pick it up or (now realising, stupidly) hit it a couple of times with the hose pipe .... you can so tell that I am NOT a gardener...

Fingers crossed I haven't seen it this year, but thank you for posting this topic and offering the info