Hibiscus mildew

Question

I have several gorgeous Luna Hibiscus in all 4 colors. They have multiplied over the past 3 years and are huge and thick this season.

They are definitely getting mildew on lower leaves and those leaves are turning yellow and have gray mildew spots on them. I am eager to treat because they JUST started blooming like crazy.

The thing is, we are having very unusual Zone 7b- North Carolina – weather. It is raining EVERY NIGHT. And it Raines the vast majority of days or nights before this – for a total of 6 (?) weeks of water-logged everything.

I can not give them the systemic Bayer formula when it must be waters in – because the ground is profoundly saturated. Also, the stems are spread out to fill an 8′ long by 3′ wide area…

I do have a sulfur spray. I do have the Bayer systemic product in the t yoe that hooks to your garden hose and sprays the plants. However, the power would kill the hibiscus. But maybe spraying underneath?

I believe the rain should slow down this week for a short break. I can treat them then. I do not think baking soda or milk or natural remedy is going to be effective against a fast spreading fungus.

I do NOT not want this year ruined. I am hoping to have a second big flush if of blooms later, but if they defoliate, I will be fortunate to keep them alive.

Note – they did get this fungus bad last year but we were unsure of the cause- the nursery lady said it looked like a spray pattern from using insecticide when it was over 90 degrees all summer. MAYBE I had BOTH a fungus and spray damage…

I used Bayer systemic last year and the leaves fell off that were agfevtrd, and then the season ended before too much longer, and the plants went dormant.

Is it possible to completely get rid of this Problem? It is amazingly humid here. I do NOT have much mulch left under the plants, just a thin layer. I try to remove affected leaves, and attempt to remove fallen flowers and foliage from under the plants – but this is very challenging.

Thank you!
Shawna

Answer 1

This article will help you.
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-has-white-fungus.htm