Once an annual has put out flowers and made seed, its purpose in life is accomplished. Pull it.

I'm getting mixed answers on Google. Some are saying that it's an annual. Period. Others are saying that in the right conditions (say, indoors) it's a perennial.

I kept my small basil plant alive all through last winter in a small pot in the kitchen (eastern sun & artificial), then replanted it outside in the spring. The leaves became thick and tough by about Feb, and the stem was very brown in the spring. Once outdoors, it was slow to get going, but eventually became bushy and productive, and I harvested it a couple more times. It was ok, but not as productive, nor as nice to look at as the newer plants.

While you *might* be able to keep it alive for longer than one growing season, it is an annual.

FataMorgana