MulchWorx Red Mulch Color Concentrate - 2,800 Sq. Ft. - Deep Burgundy Red Mulch Dye Spray

Q: Will this work on pinestraw?

It should works really well on the mulch

Q: Will it work on rubber mulch and if I have red mulch and use the black colored one will it color over it so it is not read anymore?

It will work on red rubber mulch, the rest I have no idea.

Q: Does anyone know if it can dye black mulch red?

I doubt it would. If it is faded black mulch with some black still visible, it will probably come out a black/red mix. Might be a cool look? I used it on faded red mulch and it worked well. It is very thick and must have a good sprayer to use and frequently keep shaking the mix in the sprayer to keep it blended, turns out better with less chance of nozzle clogging.