Hi! I've attached pictures of a leaf from my weigela, front and back. It's a Rainbow Sensation, Weigela 'Kolmagira'. This seems to be sporatic throughout my weigela shrubs. The shrubs look healthy expect for some of the areas. Some sort of fungus due to our weather this year? Thank you!
Yes, this does look like a fungal issue, and yes, our wet spring has made this ideal for such diseases, as well as thick bushy growth, part shade, and leaves standing wet for many hours.
You can thin the areas where this problem seems to be the worst( to promote air circulation and quicker drying), keep leaves picked up, and be sure shrubs are irrigated without leaves being wetted.
In fall rake up all debris, bag and throw it away; or you can bury it if you don’t want to bag it.
A garden fungicide will reduce fungal infections when applied early in the season. If you apply it now it will help stop the progression while we have wet conditions but not ‘cure’ affected leaves.
You can get a specific diagnosis of which disease is on the leaves by submitting fresh samples to MSU Plant Diagnostic lab. Instructions and fee schedule are here-
Thanks for using our service.