Forsythia branches dying
I have two long rows of forsythia. In these pics, the farther row (left row in the long view) is 10-12 years old. The closer (right) row is 5-7 years old. Some of the plants (just a few) have dying branches. The row section with dying branches is in a lower, wetter spot on our property. But we've had branches die farther away along the row, on higher ground. We also have a serious problem with voles in our veg and flower beds.. Could one of these conditions be the cause? Or can you suggest others? Thanks.
Forsythia are such fast-growing hardy plants that the damage in the photos is unusual.
There are a couple of diseases that could affect them. Both should be handled by pruning the dead stalks down to the ground.
We wonder if herbicide has been used nearby. 24D will float over on a breeze and kill plants. Glyphosate can kill if it gets on woody stems (or leaves.)
The grass mulch is undoubtedly encouraging the voles by providing them with cover/protection. Use traps and stop mulching. See here: https://extension.umd.edu/hgic/voles
Thanks for this help.
If it's voles, will I find evidence at the base? Or do they eat roots?
Rodents, including voles can gnaw on the base of woody plants, especially in the winter, under cover of mulch.
Voles however, can also eat roots from underneath the plant. In that case those branches and plants can often be lifted right out of the ground when they are severed from their roots. You can see photos at the link supplied above.