3 at the most - recommended planting distance for these is 35cm.

I agree with Bamboo 3 plants.

thats a very small hanging basket 12 inch you will have to water everday in the summer not boasting but mine are 16 inch you can pack all sorts in

Gg

Yes, but my daughter decided she didn't want hers so gave them to me. They grow into giant shrubs every year with huge flowers, obviously re-planted in a larger container. Beautiful.

usually 2 to 3 per hanging basket depending on how big the basket is

I would also say 3, but that won't leave room for anything else!