Linda: Have no fear about using mushroom compost on your iris beds. The best
way to apply it is to till it into the bed during initial preparation. It can
also be used as a mulch and let mother nature water in the goodies contained
When we were preparing for the '94 Portland Convention we worked in 20 cubic
yards of mushroom compost into a 50' X 70' guest bed along with other
amendments (i.e. gypsum, 10-20-20 and alfalfa pellets). The iris grew like
Regards Dave Silverberg in Oregon.