Is there any danger with heavy mulching over herbacious perenials? I have lots of perenial sunflowers, black eyed susans, bee balm, lavender and other perenials that lose all their above ground vegetation in the winter and I am worried that if I put to much mulch on them I could kill them. Is 3-6"s of wood chip, grass cutting, shredded leaf mix ok? When planting new plants, should I put them shallower in the soil to accomodate for the thicker mulch?
Thanks!