Having recently purchased a mulcher, I'm wondering if there is a
consensus to whether certain waste, like rose prunings, shouldn't be
used as mulch around other plants as they might carry disease.

For example, I wouldn't put maple clippings as mulch, they might
transmit bacterial cankers or even verticillium. I'd probably not put
rose, and although I did use a lot of willow the other day after putting
it through the machine, now I wonder if that was wise. Things like
elder or hedge laurel, give me no qualms.

So, what garden waste would be unsafe to use ground up as mulch around
trees and shrubs?

Thanks,

-E

P.S. saw the first snowdrops poking up this afternoon!