I have had a Euc come up wild in one of my training pots, I am unfamiliar with them as a bonsai but I am going to give it a shot, I reckon do the same.
I have already repotted this one and am even trying it as a root over rock. Don.t know what species mine is as yet but it is now thriving.
More natives should be trialled for the benefit of Australian bonsai.
Watty