Posted: 10/11/2014 at 16:46
I think feeding it every week is over-doing it. That's probably why you're getting lots of healthy foliage and few flowers. Producing flowers and seeds is a plants way of ensuring the survival of the species, and sometimes if it feels a little threatened it will flower well. If the plant is growing happily it sometimes doesn't bother.
I'd stop using whatever fertiliser you're using and in the early spring water in some soluble potash (as directed on the packet). Just the one dose.
Then wait and see - if you get no flowers give it a sprinkling of fish, blood & bone in mid summer and the following year another dose of potash in the spring.
Good luck, and let us know how you get on