I used to have a perennial basil, I am not sure what type it was but assume it was an interspecific hybrid as it would flower but never set seed. It was ok but did not really taste like sweet basil. It grew for a few years and I lost it recently when moving house. I have been looking for another one but will probably have to mail order it. I much prefer sweet basil though.
This got me thinking, if I got an annual sweet basil and grafted it onto a perennial basil root stock would it grow as a perennial (assuming that I removed its flowers)? Or would the scion die at the end of the season?