When to cut back alliums - Top tips to maintain your garden (2024)

FAQs

When to cut back alliums - Top tips to maintain your garden? ›

Allium flowers only bloom once per season, so for allium flower care 101, you won't need to prune the plant back until it's one flower has dried. Once the plant has bloomed, allow the bloom stalk to dry completely, pushing all of its energy back into the bulb for next year's blooms.

When to Prune Alliums. Alliums are bulbs and need to store energy in their bulb for the winter and next season's growth. After the bloom stem has died back, it can be cut off, or deadheaded, to prevent the plant from forming seeds. The remaining foliage needs to be left alone for as long as possible.

So it's important to allow these plants to die back naturally. Once the foliage has yellowed and withered, it can usually be removed with a gentle tug. When herbaceous alliums have finished blooming, use scissors or hedge shears to trim off the spent flowers.

Most Alliums will do best in full sun and well-drained soil. Plant tall Alliums in a sheltered spot to stop the stems blowing over in strong winds. In shady gardens, plant yellow-flowered Allium moly, which prefers light afternoon shade, or purple-flowering chives (Allium schoenoprasum).

Should you deadhead alliums? Like most flowers it is best to leave the foliage to naturally die back before removing any heads yourself. However alliums can sometimes have foliage that turns brown when they are in flower, in this case there is no harm in removing the dead foliage.

Once the Allium leaves have turned completely yellow and dried out, you can gently remove them. This usually occurs in summer, depending on your climate and the specific allium species. Use clean, sharp scissors or garden shears to cut off the dead foliage close to the ground.

Over time, allium bulbs will multiply and your beds might start to look a little… crowded. If your alliums are jostling for space, use a fork to dig the bulbs up after the flowers have died back. Pull a few out to divide them and plant the smaller bulbs in other areas of the garden.

You can cut off the spent flower heads at the base but this is not essential as the dried flower heads look attractive in the border.

You must be careful not to over-fertilize–this can result in weak stems also. The depth at which allium bulbs should be planted varies according to the variety and size of the bulb, but is between 4 and 8 inches generally. Shallow planting can cause the bulbs to tip, leading to flowers that fall over.

Many Allium plants will self-seed and spread if you let them (but not the Globemaster variety which is sterile). Deadhead spent blooms to prevent self-seeding.

Do alliums like full sun or shade? ›

Light: Allium thrive in full sun, but can tolerate part-shade conditions. Soil: A well-drained soil is the most important condition for allium as bulbs may rot if left in wet soil. The average soil of most garden beds kept moist but not wet is generally fine.

Water well once and wait for spring, or, when you live in hardiness zone 3-7, water well and bring the containers indoors, letting them spend the winter in a cool spot like an unheated garage or basem*nt. After the alliums have bloomed don't cut off the foliage.

Alliums tend to bloom from late spring to early summer, and have a wonderfully long bloom time. Most varieties last anywhere from two to four weeks. Alliums are also excellent cut flowers, so don't leave these bobbing, whimsical bulbs out of your cutting garden.

Alliums are plants that come back year after year, so they are perennials. They grow from bulbs, which stay dormant during winter and then start growing again in spring. This means you can enjoy their blooms for several years if you take care of them properly.

Alliums don't require dividing annually, so there's no need to dig them up every fall. The bulbs start to multiply after a couple of years so it's a good idea to refresh a clump after 3-4 years. Dig the plant up in fall and separate the bulbs along the visible division lines.

Pruning summer alliums

If desired, scraggly foliage can be cut back after flowering to encourage a fresh surge of growth. Otherwise, cut faded dormant leaves back to the ground during fall cleanup.