It seems the word mahogany is used primarily for the type of lumber these trees produce.
Actually, it is
properly used for lumber produced from the genus
Swietenia (note what Leo said above)
However, since countries have long ago discovered that calling something "mahagony" (whether or not the species is even marginally related to Swietenia) can double the price of their lumber, there is now something called "mahogany" from just about every tropical country on the planet. Africa "mahagony", Phillipines "mahagony", etc. Some of the woods may or may not bare a resemblance to genuine mahogany... but they are not the genuine article. (With the exception being that there are supposedly Swietania plantations in Fiji and India made entirely from transplanted Swietenia trees)
I should almost sticky a thread because we have talked about this subject at least three times previously. Suffice it to say genuine mahogany is quite expensive - and
Swietenia mahagoni has not been commercially available since the 1950's. For woodworkers like myself, going into a reputable tropical hardwood store, the lumber is always listed by species, not common name. So there is no such thing as "African mahogany" since I buy it as
Entandrophragma cylindricum.
And I do not think the OP was intending to mislead, rather he was just repeating what a misinformed nurseryman was telling him. Apparently the glamor of "mahogany" is now even extending to landscaping material
FWIW, genuine mahogany IS a Florida native, and IS available for sale in the US. You just have to make sure you are buying
Swietenia mahagoni. If it isn't called "mahagoni" it isn't the genuine Florida native. The other Swietania species are from Central America.
And to top it all off... I don't consider
Swietania mahagoni a particularly suitable tree for bonsai - because it has large compound leaves. But that is a topic for another day, LOL!