Spruce tree chips
Is there any harm to certain plants if using spruce tree chips as mulch?
Potter County Pennsylvania
Thank you for your question. In researching an answer for you, this response, from an "Ask an Expert" dialog a few years ago showed up:
Wood chips are a wonderful mulch for some purposes, so thank you for asking about your situation. The answer about using spruce wood chips is "it depends". What will you be planting? What is the sun exposure, slope, soil and water situation?
Here are articles from the Oregon State University Extension Service about gardening with mulch and the sheet-mulch, or "lasagna-style" mulching. Read through these, they will help you understand what sort of issues we should look at....or perhaps the information will resolve your questions.
'Publication answers mulching questions': http://extension.oregonstate.edu/gardening/node/1044 and
'Layer compost 'lasagna-style' for no-till gardening': http://extension.oregonstate.edu/gardening/layer-compost-lasagna-style-no-till-gardening
Specifically, is there any chemical or rosin in the spruce chips that will kill some plants?
I can find no chemical reason you couldn't use spruce chips - please read the following:
You can mulch around trees with standard bark mulch, or you can use wood chips or shredded leaves. There is nothing wrong with using wood-chip mulches as long as you age them first.
Around large, established trees and shrubs and in places where no desirable vegetation is growing, like on walkways, there is no problem with applying fresh wood mulch. If the wood is going to be used around annual garden crops or ornamentals and tilled into the soil at the end of the growing season, let the mulch age for several months, ideally encouraging some decomposition by adding "green," or relatively nitrogen-rich materials like table scraps and fresh grass clippings, to the wood and flipping the material occasionally. To use the wood as a soil amendment, the wood should be completely composted, with a dark, crumbly and uniform texture with no recognizable pieces of wood or other materials. Fresh wood mulch ties up nitrogen as it starts to decompose, although it will eventually become a source of nitrogen itself, so it should be aged before applying it around shallow-rooted, young plants.