I planted my Campsis Radicans seven years ago. It is sited on a corner of my house in Wiltshire in fairly light soil on green sand where it gets full sun for at least eight hours per day during the summer. It puts on terrific growth every year, eight foot on a trellis, then clinging to the wall ( or trying to) up to a height of fifteen feet plus. At the end of the season I cut it back to the top of the trellis. It has never shown the slightest inclination to flower. I thought I had over-fed it so have not done so for four years though it may pinch some food from a neighbouring rose. The only other plant of this type that I have observed appeared to be pruned severely every year. Any suggestions?