Then lay down about six layers of newspaper overlapping so there are no thin spots. The compost mulch looks better, it keep the newspaper in place and it provides a measure of protection. At one time, newspaper ink was petroleum based and would have injured the soil environment. The use of newspaper with colored inks should be avoided. It is about the advantages and disadvantages of these various mechanical control methods and when their use is appropriate.
Top growth generates plant nutrients which, for the most part, are stored in the roots.
In the case of annuals, remove the top growth just before it sets seed. Plant energy at that time is being channeled into flower and seed embryo production with little left over to replace top growth. In the case of perennials, the removal of top growth forces the roots to give up nutrients to develop new stems and leaves. There is a limit to how many times roots can initiate new foliage in a single season. Primarily, this includes soil solariazation and flaming.