Kathleen I've been reading hundreds of articles relative to using any parts of Black Walnuts as compost or mulch. The general consensus of information on BW bark Mulch seems to be that 2 months decompose time is adequate if it has been exposed to the elements. So if you have a big pile, you should either keep turning it, or use the top layer of it so that the next layer will get exposed to air and rain. If the underneath of the pile is not "hot" composted, or exposed to the elements, the bark can hold the Juglone for quite some time.
