I buy plants from the local greenhouse which is privately owned. I probably pay a little more that at the big boxes but he has lots of greenhouses, his plants are started early and are quite hardy; by the time I get them they are strong stemed and often in flower. With our late season, although there is some variability depending on variety, they typically take a long time but I usually get 6 -10 on a bush and have to stake them. Do you pick off the suckers like with tomatoes? Once it is apparent that they are fully bloomed, I fertilize only with low nitrogen to limit leaf growth and pick off any suckers. For some reason they seem to like to be mingled with tomato plants as well. Both enjoy basil.