Good Morning Ellen, 

Thank you for contacting the U of M Extension Service. 

Are the weigelas near each other? Could this be herbicide drift of pesticide drift? Did you witness the leaves on the dead plant dying and falling off? When were they planted?  Did they all leaf out in the spring? Are they getting enough sun? Were the roots protected over winter with some type of mulch?  Is someone's dog relieving themselves on your shrubs?  

Please click on the following link from the U of M Extension Yard and Garden website: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/weigelea/index.html  This is the result of working through "What's wrong with my plant?". 

You might do a very thorough inspection of the plants and leaves based on the above information to see if you identify any specific problem. 

Good Luck!

Hi, Thanks for the quick reply. I have 3 weigelas planted near each other. One is dead, the one next to it is dying and the third is starting to show damage. I have 3 more on the other side of the sidewalk and the closest one is starting to look damaged. All of them were mulched last fall and had leaves this spring. All 3 are in full sun and rain has been plentiful. The leaves began to disappear and the stems turned black on the first one. The leaves didn't fall off. They were just gone. If a dog was peeing on them, it seems like the leaves would turn brown or fall off. 

The other misc. shrubs around the weigelas are fine. My neighbors and I don't use herbicide. I did spray the two healthier shrubs with a Bonide bug spray in case that would help, but it hasn't made any noticeable difference. The torrential rain we keep having might have washed it off. I would appreciate any treatment suggestions.

Thanks!

Good Morning Ellen, 

Here is another link about weigelas: https://plants.ces.ncsu.edu/plants/weigela-florida/

Since the plants are near each other along a sidewalk, I think it is some kind of a problem with the environment. Would they have received salt residue from the sidewalk? Is the soil around them draining adequately with the rain we've been having?  

I would not use a pesticide spray on the plants unless you have identified a specific pest. ALWAYS READ THE LABEL for what the pesticide is supposed to help with. 

Again, you might do a very thorough inspection of the plants and leaves based on the above information to see if you identify any specific problem. This could include digging up the dead one to see if there is damage to the roots, or if it was planted too deep. 

Good Luck!