Can I use mulch made from recycled tires?
To me this seems a real environmental no-no–yet another wacky thing that is being tried out on us unsuspecting consumers. Yes, it’s re-using worn tires…but putting them into the landscape, and nature, in shreds is as bad or worse as piling them up at the dump whole. They don’t break down and become incorporated into the soil, so they’re no good, and even dangerous. Remember that animals and much smaller living organisms interact with and inhabit the soil–I don’t think a worm wants to process tire shreds while making worm castings, or a robin wants to rustle around in the tire litter (though they love the leaf litter!).
My rule: To be a mulch, it must be organic (a living/formerly living material) so it can decompose over time and return to the soil, not taint it. The one exception to my mind re: the organic rule would be some stone materials used in certain zones and certain types of landscapes.