The electric company removed three big Weeping Willow trees from our property last summer - they were getting into the power lines by the road. They had a giant chipper on a trailer and chipped up the limbs. I had them leave the chips here in a big pile, for future use as mulch.
Turns out, willow is a very soft and light wood. That pile of chips is light grey and the wood chips are intact on the outside of the pile, but just a few inches down the chips are damp, soft, and black - really falling apart and turning into sawdust and black soil. It has a nice smell to it like sawdust, and from the smell there's quite a bit of tannin present.
Right now, I'm pulling weeds in my garden rows and putting down grass-clippings mulch. I've tilled the paths in the garden several times to control crabgrass and weeds, and so far I've only put grass clippings in the rows themselves, around my veggies. When I finish doing that, I'll put mulch in the paths too, so I don't have to fight weeds all season.
Now I'm wondering about mulching my garden paths with those broken-down willow chips instead of grass. I can move the chips with my tractor bucket, and it'd be a lot easier to do that. Since I'll be keeping it away from the plants, there wouldn't be any effect on this year's garden - but at the end of the season it'll all get tilled in. If there's anything toxic in those chips (like if they were walnut) I could ruin my whole garden for future seasons.
I don't THINK there's anything toxic about willow. Pasture grass has grown right up to that chip pile, and grass is growing up through the edges where the chips are only a couple of inches thick. Also, I noticed a few little seedlings (poison ivy, elm, and wild plum) are starting to grow on top of the pile itself.
What do you think? Can I safely mulch my garden paths with this, then plow it under in the fall?