If it is from seed then it makes it doubly difficult. There are a large amount of different named cultivars here in Aus, ranging from around 30cm high to over 1.8m tall. Even limited in a pot, I would expect the green that I was thinking of to be pretty tall (maybe a metre or so). Species range from 20cm up to 1.8+m, so there is a lot of range for hybridisation, particularly depending where the seed actually came from and what it involved. The flower you've shown is spot on for the green one I was thinking of, but I really have no idea of how many different greens there are. Sorry I can't be more certain, nor able to identify fully for you.