The azalea bushes I have are about 15 yrs old (they were put in when we had the
house built). They have gotten very big (we have trimmed them back some over
the years).

They just don't seem to be full and full of flowers like they were when they
were the first couple of years. Is there anything I can use on them now to
help them get "fuller". I would say our soil is kind of hard where they are
planted but we do mulch around the plants.