We have a small area next to the house (in the Cleveland, Ohio, region),
where my wife has planted petunias for the second year in a row. It gets
sun part of the day. Last year, the flowers lourished and eventually
covered the entire surface. However, before they had proliferated, one
could see the hardened, dreary-looking soil. So this year, I added mulch.
Looks great.

Now, the flowers did not expand at all this year, and a bush in this area
died rather quickly at the beginning of the summer. A neighbor and my wife
claim that it is the mulch that hampered the growth, and my question is if
this could be the case. It needs to be mentioned that we have had a lot of
rain this year, that there is no slope in this area, that the
humus/soil-cover is rather thin, and that there is clay underneath.

Thanks -- Hans L