Those are just the regular impatiens. I can't remember what type they are. I save seeds from them every year and start them early indoors and put them out when it's warm enough.
The only problem I had with them was with the floating island. They almost all died at first, turning yellow and not growing. I've not been able to have any floating plants survive for several years now.
I asked a friend who happens to be a landscaper, and he said they looked like they had an iron deficiency. He told me that the ones in the waterfall were picking up iron from the rocks, so they were doing well.
So I got an iron test for the pond, and there was zero iron in the water. I quickly realized that I would go broke trying to treat the entire pond. I would pour in the correct amount of chelated iron and test the water 15 minutes later. Zero iron! The plants were taking it up as quickly as I was adding it.
I started spraying the leaves of the plants regularly, and that island is the result. Now maybe I can grow more floating plants in there as long as I spray them with the iron solution.