[Yorky]

A friend has had a purple flowering passion flower plant in their conservatory for many years and then three years ago they added a Blue Passion Flower (Passiflora caerulea) to the same conservatory border. The original plant flowered prolifically each year until this year when the later addition seems to have taken over.

The original plant is hardly flowering at all now and the new one is only flowering moderately but has plenty of leaf growth.

I suggested that it needs a high-potassium feed to promote flowering. Is this correct or should the latter plant be removed? If so, how can this be done without damaging the original plant?

Thanks in advance.