I planted some Spring Onions a year ago and all three have bloomed this year. One of them even went as far as providing a head full of seed. I have those seed collected and placed them in starter pots to see if I can get more growing, but ever since blooming, my spring onions have continued growing and providing me with stalks for cooking.

Some people cut the flower heads off to make bigger bulbs. The onions should be ready to harvest when the foliage dries up and falls over.