What to Do With Alliums after Flowering

What to Do With Alliums after Flowering

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Alliums have a distinct look, taste and smell. They are typically used for decorative purposes and depending on the species, they can be used as food crops but I’ve always grown ornamental alliums and really enjoy the larger flowered varieties although I do have a selection of smaller growing varieties too.  

Do you enjoy the sight of alliums? If you already have them in your garden they are magnificent, but what do you do with alliums after flowering?

Allium just finishing flowering

Those who have managed to cultivate alliums successfully know that winter can sometimes damage the bulbs; therefore, leading to lesser blooms during the flowering season. This is especially true if you don’t cut them back at the right time or give them adequate protection over winter when needed.

To ensure fantastic flowers the following year you must understand which steps to take. My guide below will be of help in this regard, so let me begin:

Tending to Alliums after flowering

Giant Onion (Allium Giganteum) after blooming in a garden ready to be cut back for winter

After alliums display the magnificence of their blooms, they start to decline in terms of appearance. You should remove the flowers and let the leaves remain intact until they die back ad turn brown naturally, never remove the leaves before as this is how they put goodness back onto the bulb.

Regardless of the flowering phase ending, it is essential to keep the plants watered until they start yellowing. Many people make the mistake of removing the yellowing leaves before they die off, thus affecting the plant’s ability to store adequate food for winter.

When the leaves and the stems die off, the next step is to cut back them down to the ground, noting where the bulbs are located. You have the option to divide the bulbs and replant them in new positions to promote optimal growth. I recommend dividing the bulbs every three to four years to avoid damaging the original plant and keep them looking their best. You can always give some bulbs to families and friends if you have too many as I do.

Caring for Allium bulbs before winter

Alliums, which are related to onions and garlic typically, flower around spring or early summer, lasting for about three weeks so flowering is generally short but not many plants can complete with the flowers of alliums. They require well-drained soil for optimal growth and enjoy long exposure to the sun. To make sure the bulbs flower in the coming season, you should deadhead the blooms and leave the foliage in place as previously mentioned.

Understanding the exact location of the allium bulbs prevents you from damaging them accidentally by digging. There are those of us who are quite forgetful (me included), so make sure you leave a mark somewhere to avoid digging them up by mistake. If you don’t care for such measures, just plant the alliums amongst late-blooming flowers to maintain the appearance of the garden before they grow back.

Protecting alliums from winter

Although hardy, Allium bulbs in the ground need some feed and mulch to ensure they survive the winter. Mulch acts as a heat insulator that prevents the cold from damaging the bulbs in the ground but also helps the soil retain moisture but it is important that the soil does not get waterlogged.

If you have your alliums in planters, you must move them from the open and place them in a sheltered area. This is because compared to the bulbs in the ground; potted alliums cannot take advantage of the heat stored in the ground. When the sun shines, the earth retains some heat thus ensuring the cold does not wipe out the plants.

You can place potted alliums in a conservatory, cold frame or small greenhouse if you don’t want them to risk any damage.

Read next: How to divide agapanthus to encourage more flowers

Dividing alliums every 3 to 4 years to keep them at their best

Allium bulbs after dividing being replanted in new positions

Alliums are not hard plants to grow and to make matters better; they are fairly drought tolerant. Whilst alliums are easy to grow, overcrowded bulbs can affect their blooms. Overcrowded alliums will struggle for nutrients, therefore, reducing the blooms every season. I try to divide my bulbs once every 3-4 years to ensure the plants get enough nutrients and it makes the garden look less crowded.

You should divide bulbs around autumn when the foliage has shrivelled naturally, this is when you would usually cut the foliage back to ground level. To divide alliums, carefully dig around the main plant taking care not to damage the bulbs.

Once you have the bulbs at hand, divide them with your hands, and transfer them to different locations or planters. It is better if you transfer the bulbs to new locations immediately, although they can be stored for a while if needed, in a cold dry place.

Before replanting the bulbs, add some fertiliser to the area to give the bulbs enough nutrients for the following flowering season. Add some mulch for moisture retention but ensure to clear the mulch once new growth begins to provide open space for growth.

Plant the bulbs deep enough (preferably three times the height of the bulb) as this ensures that the root system is anchored securely.

If you also have lilies, you can also learn what to do with Lillies after flowering here


Alliums have a unique flower that will definitely add some architectural balance to any decorative arrangement. These plants are not only decorative, but they do an excellent job in deterring garden rodents, aphids, and the Japanese beetle.

If you take care of your alliums, you will enjoy both a magnificent blooming scene and protection from unwanted pest harassment.

Read next: How and when to divide Alstroemeria

Read next: How to keep calla lily bulbs over winter

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