Dear all, a query

I have had my garden for 17 years, and in the early days made it nice
and tidy, and when parenthood came along got into the "mow the grass
now and again and forget to prune" mode that I imagine many of you
have experienced ?

Now, its the time to get serious again. I spent the winter hard
landscaping, the early spring re turfing areas, redefining borders
etc, and have now got everything in place. I am happy with the results
of my work.

Now, my question.

Does the type of feed you use make any difference, or does using it
make any diference ?

One of my borders that I have left untouched (perenials) has grown and
died happily for the last decade. It looks neater now, and its had
some growmore and mulch, but I am unsure its made much difference to
the speed or strength of the growth to date.

I understand the constituent parts of fertilser, and the supposed
effect on foiliage/roots/flowers, but does it make ant REAL differnce
using Growmore 7-7-7, Miracle grow (bigger numbers), blood/fish/bone
(lower numbers) or nothing (nothing !)

I am quite addictive, and I could easily see myself knocking up my own
fertiliser from consituent parts, or using straight potash etc, but
dont really want to, so help me out

My priority is nice flowers and full borders...not that bothered about
being organic at the expense of lush borders (I have seen the scrawny
carrots in tesco ), but would like to hear your views on this, as the
array of boxes is enormous.