Roots, bark and herbs with tough stems and seeds don’t really work in the method of infusing. Decocting is boiling and then evaporating by simmering slowly to produce the most concentrated liquid which is excellent in medicines. I even use my humble crock pot for these slow brews.
Use a coffee grinder for roots and small pieces of bark and stems to make quick work of these.
I recommend the decoction method for the roots of willow, sarsaparilla, wild cherry, yohimbe, yucca, licorice, parsley, dandelion, angelica and cohosh.