I'am also an avid plant collector,and have simply bought plants because of that bewitching enchantment that totally beguiles me every time i set foot in a nursery or garden centre, to add to the eclectic mixture of of plants, that is my garden. For example i like black plants and couldn't help falling for two brand new black sedums called Sedum 'Xenox'& Sedum x 'Postman's Pride' respectivley, but don't care that they're not in the some designers concept of how a tropical garden should look, you should collect the plants you want, and plant them where you think they look best. Don't be a sheep, garden the way you want, after all you're the one who's got to look at it all year,enjoy.
p.s. happy new year to everyone, lets hope this year will be a little drier!