We have an enclosed bed on our patio, south-facing and partly sheltered from winds, though still somewhat exposed. Dimensions: 6m length, 1.80m depth and with a depth of soil of 80cm. At the moment it is planted with one of each: Pittosporum tobira, Plumbago capensis, Hibiscus rosa-sinensis, Nerium oleander, a jasmine and 3 geraniums (Pelargonium x hortorum). The problem is that, although all plants grew well and are 1.50-2m tall, they are now showing signs of struggling, apart from the plumbago, which has become a thug and taking over the whole bed with runners. We are considering getting rid of the plumbago and perhaps replacing the geraniums which have become tall and leggy. In the past we also had a Lantana camara which became a thug as well and was removed.
We have thought of the following but have some doubts about them:
Campsis radicans or grandiflora - we have not succeeded with it in the past but have read that it can also become invasive;
Podranea ricasoliana -we used to have it in the bed before it was strangled by the plumbago;
Cestrum nocturnum - will the scent be too overpowering, considering it would be close to bedrooms?
Another jasmine - untidy? how will it cope with winds?
Bougainvillea - drops lots of dry bracts/ would have to be fairly compact.
Mandevilla laxa
Solanum jasminoides
Ideally we would like both colour and scent.
Any suggestions? Have members had negative experiences with any of the above plants in enclosed beds?