Most off the salvia farinacea cultivars come true from seed, so go ahead and collect seed.

Hi greenmum-I love Victoria blue, too. I have been using it in my garden now for many years. Up until a few years ago, however, I didn't realize that my salvias would come back from their roots if only I would leave them in the ground. One year, I accidently left them in the ground over the winter months (didn't get around to yanking them out, like usual). Boy, was I surprised when they came back the next year, bigger and better! You might try this as well. I ended up yanking them from that bed, anyway, as I changed out all my plantings in that particular bed-but those salvia roots were huge. Not sure if this will work for you, since you live in Canada-but since you list yourself also as zone 7, it can't hurt to try it. I was very pleasantly surprised. I again planted VB in this bed this year-so I'm very interested to see if I get the same results next spring-got my fingers crossed!