Charlie Pridham wrote:
La Puce, try increasing light levels if you can, stop using pelleted chicken
manure as it encourages growth rather than flower, prune only in July/August
not in the winter or bend some stems down and train horizontally and be
patient, they all flower eventually :~)

Thank you very much for the info. The profusion of leaves this year is
evident that I do something wrong. I've made a fan shaped trellis above
the porch in the hope that it would be covered of flowers ... I will
prune it but why bend some stems down? Do they prefer flowering
horizontally?