I am waiting like a spider for information this post might generate. They are perennial here and I have lots of them in all conditions. I have leggie ones that bloom on the ends from last year. I have in the past staked them up and planted around them, looks great. Some will eventually fill to the root later others never do. I have two identical pots with petunia, calibrachoa and verbena. In one pot the calibrachoa has small leaves and flowers and wilts in the middle of the day. Everybody else in the pot is robust. I don't understand how I got such a big plant from cuttings and it's slowly dying. It's sister pot is going strong. I wondered if the bad pot got dry but realized the problem has been going on for a while because of the small leaves and flowers They get aphids and snails love them. When they do well they do very well. They take some frost and gain size in cool spring weather. They like a lot of sun but not heat, coastal. But I have had them suddenly die. I know you can drown them and they are big time feeders like their sisters petunias. I have several in pots that are just a mound of color now. We have had one in the ground at the foot of the big grape for 7 years? It stops blooming in summer maybe from heat, less light because the tree leafs out or maybe it isn't a fancy one. Hybridizers do a lot of work on them and they vary a lot. The newer ones bloom a lot more and are more heat resistant.
Well I am sick and tired of putting up with the bad behaviors. Some hair cuts have started. This afternoon the ones with bare feet will be trimmed for cuttings. I planted one in a hanging basket this morning to see how that works. After thinking about all my experiences with them I will start treating them like petunias, regular haircuts and feedings. Slow release fertilizer in the pot 18-6-12 and liquid feeds 20-20-20 more frequent as summer heats up. Bait for snails and for those small slugs that never hit the ground spray with 10% ammonia solution at dusk. Earwigs can be murdered with oil spray. I will also move some to shade in July when we start getting those *100+ days. Everything grows differently in different climates. It is hot and dry in summer here, Mediterranean climate.
I would like someone to explain the sudden death syndrome. Info please!