Everything. And the weirder or esoteric the better. Dietes, Siberian Iris. And I also like challenges. So tropical seeds are fun for me. This year I grew a Rainbow Eucalyptus which I will try bonsai. I also do a lot of after dinner growing - e.g. kiwi, pomegranate, pineapple from seed. Dozens of others.
I do have a lot of failures though. I grew some of Calotropis gigantea last year, but they perished over-wintering in my garage.
Guess it was too cold.
I tried the notoriously hard Welwitschia mirabilis and joined the group that fail trying it from seed. Neat plant though. Would love to have one.
