I'd be interested too in how to get campsis flowering abundantly. Back in the UK we never ever got flowers on the one we planted. Even here in France the one we planted by a wall has never grown well and only produces the odd flower. Yet a kilometre from here there is a campsis growing along the roadside that is about thirty metres long and decked with flowers.
I guess it must be to do with sunshine and soil. It will be good to hear from someone who is successful with this plant.

We had a huge Campsis x tagliabuana 'Madame Galen' in London that flowered prolifically without any special treatment whatsoever - thrived on neglect you could say!! It was planted against a hot, south-facing brick wall.

I've also used them in other gardens with success, but being late summer to autumn flowering they definitely require a sunny, south-facing position both to flower and also to ripen growth successfully before winter.

I've been considering getting one - keeping tabs on any useful answers for future reference.

The more sun, the better! they even bloom better on south-facing walls here in the desert!

I planted a 'campsis radicans 'Flava' (yellow one) in 1999, and it only started flowering in 2007! just a few flowers at first now blooms every year (not prolific) I leave it alone to climb up a dead tree, never cut it back. maybe I should!! It has 8 bunches of flowers at the moment. it is growing on heavy clay soil so maybe that's why it took so long to flower.