New Perennials Dying
I live in Western Saskatchewan and planted new perennials this spring. The one flower bed faces south and the other is on the west this all near the house. They were doing really good and then I put wood shavings and since then some of them are dying back not all but some, I have Fox gloves, Dianthus, Phlox, Columbines, Blue oat grass, Russian sage, bleeding heart, Evening primerose. Also my flower bed in the North corner of our back yard and they also were doing good until the wood shavings and in that flower bed is Astilbes, ground phlox
Doug says why plants die is a mystery to many people but the deal here is probably pretty simple. You put wood chips on - and then reduced the watering. Without adequate water, the plants suffer.
Or you put wood chips on and continued to water like crazy - and you managed to hold too much moisture around the crowns of the plants and rotted them out. Never cover over your plant crowns with mulch - let them breathe and drain.
Or - there was something toxic in the wood chips.
But generally, I'd stick with the first two options and it's a gardening management issue rather than a wood chip problem.