It means that something that is good does not need advertising.
Ancient Greek wine sellers used to hang a branch of ivy outside to advertise their wine shop (in the way that shops still have signs to advertise their contents).
Good wine needs no bush is a phrase that has been used by Shakespear and others, but I wouldn't say it is all that current, in British English, anyway. I'd never heard of it and went on an internet search for this info.