I've figured out the Life Cycle of the Leeks, and how you can grow your own. Recall I saved the leek bottoms and planted in garden, they would grow for awhile, send up a flower stalk, and die off. Apparently, as Plumerias stated, leeks have a two-year life cycle, in which they flower the second year before dying,
So the leeks were allowed to continue growing, and sending up the flower stalk. The stalks would eventually bend over gracefully toward the ground. At this point, instead of flowering the bud formed a dense-bundle of leek "slips". It seems to be looking for soft ground, so I stuck them in a pot to root
Note curved stalk that starts upward, then curves back down (into the pot!).
Once rooted, the slips can be removed
Now I have thirty leek slips growing individually
in the garden. The summers might be too hot in San Jose, but if they make it through the next couple months, they should grow into the mild winter. And, another set of slips
is rooting for the next crop, with more sets on the way.