Some of the onion “sets” that you planted this spring may have grown into flowering plants, each of their stalks capped by starburst clusters of lily-white blossoms.

Rip these plants out of the ground and bring the stalks indoors to put in a vase. The smell of the flowers is pure onion, but they do look pretty.

Of course, if you were going to grow onions just for their flowers, there are other species of Allium — the onion genus — with prettier flowers, and the plants have the advantage of being perennials. For a dainty Allium, there is the lily leek, with bright yellow flowers, or the daffodil onion, with a dark eye in the center of each star-shaped flower. Both grow only 18 inches tall.

Some of the perennial flowering onions have tall stalks capped with gigantic clusters of colorful blossoms. Living up to its name is the giant onion, a lavender ball of flowers a half-foot across. The Persian onion has equally large, or larger, flowering heads, in purple or amethyst, respectively.

Even if you wanted to grow an Allium that you could eat, there are prettier choices than the common eating onion, and even they are perennial. Garlic chives sends up a dainty stalk capped with white flowers from its base of strappy, onion-y leaves. More familiar is regular chives, with its dainty balls of rose-violet flowers.

Let’s get back to those edible onions that flowered: Why rip them out of the ground? Edible onion is a biennial plant, making a fleshy bulb the season the seed is planted, then going dormant for winter. The following season, the plant absorbs food stored in that bulb to make flowers, then seeds. Onions that flower do not make bulbs.

Gardeners play a little trick on onions when they grow them from sets rather than seeds. Nurseries produce sets by planting onions seeds very close together. With all that competition for food and water, none of the crowded plants grow very big. The small bulbs go dormant as their leaves die down, we buy and plant these sets the next spring, and that summer they become the fat, juicy onion bulbs that they tried to become the previous season.

Poor quality sets have not been fooled, so go ahead and flower their second season. Ideally, onion set should be between 1/2- and 5/8-inch in diameter in order to make bulbs rather than flowers.