Walking onions will usually send up a stalk in their first year, but the bulbils - if any - will most likely be small. IMO it is best to break off the end of the stalk the first year (leaving most of the stalk intact), so that all of the plant's energy will be directed to making a bigger bulb.

The bulbils should reach normal size in the second year.

What he said. My established plants are twice the size and more of the bulbils, I planted last fall, and the established ones are starting to show scapes already here in Minneapolis. Last year some of the established plants had bulbils on over an inch in diameter. New plants will not have that size but once the clumps are established, the bulbil size increases dramatically.

When it comes down to it, you can really treat your walking onions pretty much however you want, including complete neglect. They are about as trouble free a vegetable as you can plant. If you want more plants let the bulbils mature and just break them off into the bed where you want them. I sorta doubt setting bulbils reduces bulb size much.

In the future you might plant your bulbils in the fall or even late summer for the next spring's green onions. Where you are, you might very well be able to have green onions most of the winter that way.

I let the bulbils grow to however big they get, then when fully ripe I snap them off and plant them - expanding the plant numbers. These things are best for green onions, so I really don't care how big the bulbs get - large bulbs make the worst green onions for eating. Those small bulbil clumps, planted whole, actually make the best, slim, tender green onions for most uses. I only keep maybe 20 of the large bulbs growing in a harvested spot each year, but I plant lots and lost of bulbils, including the really large ones from the established bulbs that I break apart and plant, and the smaller clumps that make the best green onions. Everything else is harvested and eaten. I replant bulbils throughout the year to keep the green onions coming almost all year.

Thanks everyone for the advice. Just to be clear here, there aren't even real bulbils on the flower stalk, they're just green twisty shoots with practically no bulb at the base . I think I will go ahead and snip them off, then try growing bulbils starting next year, since I've already got a ton of good leaves from the plants that are established now.

I bought a few sets like maybe 9, from Ebay. In spring they were tiny, but they had roots. Once planted, they grew. Since that time we have never been without green onions. We planted the twisty little babies and now we have dozens more. Next year, I'll be gifting the babies to family. These are the easiest onions ever to grow. Walk like an Egyptian!

It does take a little bit of time for the topsets to form on the scape. It's not like they are there from the get go.

Rodney