QUESTION: Do alliums like garlic and onions flower more than once? I’m wondering whether to leave my alliums in the ground after they’ve already flowered. — Linda A.
ANSWER: Alliums usually flower just once per season. However, if you let some of the flowers develop into seed heads, alliums will self seed so new plants will return next year. If you want your alliums to flower more than once in a single season, you’ll have to take especially good care of them and select the right strain of alliums for your garden.
How to Encourage a Second Bloom From Your Alliums
If you want to promote a second wave of blooms from your allium plants, allow the leaves to shrivel and die back on their own. Once the foliage has died back completely, it should be easy to pull it away from the plant with a soft tug. But you can go ahead and clip off spent blossoms with garden shears or hedge trimmers to encourage a second wave of blossoms.
The plant is extracting nutrients from the spent leaves during this process, so it needs for the leaves to remain attached to the plant as the foliage dies back. Some gardeners find the withered leaves to be unattractive, so if you think you’ll be bothered by them, plant some late-blooming plants that will hide the allium foliage during this time. Removing the shriveled foliage too soon can interfere with the blooming process in subsequent seasons because you will be starving the plant of nutrients it needs during its dormant period.
How to Encourage Your Alliums to Return Next Year
If you want to encourage your alliums to return the next year, there are tricks you can employ as well. Choose a species to grow that has been bred to do well in your own climate. In addition to considering the area where you garden, you should also look for strains of alliums that will do well in the soil and sun conditions of your garden. Finally, choose a strain of onions that’s winter hardy, and you’ll be likely to see alliums returning to grace your garden next year.
Even if you select a winter hardy allium plant to grow, there’s a lot you can do to keep your plants safe when the weather gets really cold. Plants in containers are especially prone to damage from cold weather. You can move them to a cold frame or protected location, such as a porch or shed.
Plants that are growing directly in the ground will benefit from two or three inches of mulch to keep the soil warm and make moisture more available. Just make sure not to touch the foliage of your plants with the mulch. Instead, leave a border of a few inches between your mulch and the plants. Allowing them to touch promotes plant diseases.
Now you know that although alliums generally just flower once, there are ways to coddle the plants and encourage a second bloom. You’ve also learned how to overwinter your alliums so they can return to bloom again the following season. Soon you’ll be harvesting lots of onions, garlic, and chives from your garden.