How To Care For Allium Plants

No matter if they are beautiful or not, alliums can be multiplied through seed, bulbs, or division. As they normally don’t blossom for at least a year or two, if not more in some situations, starting from seed demands patience.

Also bear in mind that if a plant in your garden is a hybrid type, seeds you save from it could not grow true to the parent plant.

Provide well-draining, somewhat sandy soil for these lovely bloomers. If your yard is made of hard clay, add some sand to assist drainage because they don’t thrive there.

To find out whether you need to amend the soil, you could also wish to perform a soil test.

Flowering alliums only require well-draining soil, but you should make any necessary adjustments if your soil is substantially deficient in any of the three major nutrients: potassium (K), phosphorus (P), or nitrogen (N).

From Seed

You can buy seeds or use the ones you’ve saved from a prior growing season (more on that below).

After any chance of frost has passed in the spring, soften the soil where you want your plants to grow and scatter the seeds over it. Don’t bother properly spreading the seeds one at a time because they are little. Simply disseminate them widely over the growth area.

To avoid disturbing the seeds, cover them with 1/4 inch of dirt and water them thoroughly using your hose’s soaker attachment. Till the first green sprouts appear, keep the soil moist. After that, you can cut back on watering so that the top inch of soil can gradually dry out between applications.

Once the plants have emerged, thin them to the suggested spacing specified on the seed packet. The space required for different sizes of alliums vary.

By Division

Allium plant division is a fall task. It’s a good idea to divide your plants every three to four years to maintain their health and make sure they are evenly spaced.

At the end of the growth season, four to six weeks before the first frost, trimming back any remaining leaves and flower heads is the first step.

Allow a six-inch space around each plant as you excavate nine inches down. Although the roots of ornamental alliums are not particularly deep, you should try to minimize disturbance.

Remember that alliums can develop from rhizomes or bulbs, as was already indicated, but the procedure for digging them up and splitting them is the same for both.

Lift the soil mound with your shovel, then gently pry the bulbs or rhizomes out.

Put one of the bulbs back where it was growing after separating the others, at the same planting depth as before you dug it up. If you haven’t treated your plants in several years, mix a little bulb fertilizer with the soil.

Rhizomes can be divided by cutting them in half with a sharp knife. Reposition one of the rhizomes’ halves at the same depth where it was developing.

Plant the extra bulbs the same way you would new bulbs or transplants, which we discuss in the section after this one.

If you are unable to plant the bulbs immediately away, keep them in a cool, dark place for a few months. Rhizomes can be kept in the refrigerator for about a week in a plastic bag.

Planting Bulbs or Rhizomes

The procedure for planting bulbs is the same whether you purchase them from a neighborhood store, online, from a friend, or through division.

If you haven’t tested your soil, be important to do so before planting in the late summer to see if any supplements are needed.

Fork or shovel the ground in the fall, six to eight weeks before the first frost.

If desired, incorporate some bulb fertilizer, such as Jobe’s Organics Bulb Fertilizer, which is sold on Amazon.

After they bloom, how should alliums be cared for?

Post-bloom maintenance for alliums is quite simple. Simply continue to water the plants sparingly until they start to shrivel and turn yellow. At this point, you have the option of either dividing the plants or cutting them all the way to the ground.

Divide allium bulbs every three to four years. Simply use a shovel to dig around the plant and lift the bulbs out. You should see a group of bulbs that you may gently separate with your hands. Replant a few in the same location, and immediately transplant the others to different sites.

It’s considerably simpler to take care of allium bulbs that you don’t wish to divide. When the foliage starts to fade, simply trim it back, and in the fall, mulch the soil with 2 to 3 inches (5-7.5 cm) of material. In the spring, remove the mulch to allow room for fresh growth.

Do alliums reappear each year?

The foliage of the allium often appears at least a month before the flowers do. Some species’ foliage starts to turn yellow and die off before the flowers are fully open. Plant the bulbs with other plants that will obscure the wilting foliage to help mask it. Alliums do well with hosta, astilbe, and perennial geranium.

When your alliums are blooming, you may anticipate seeing a lot of pollinators. Any type of habitat garden will benefit greatly from the inclusion of these bulbs.

Like their relatives in the vegetable garden, alliums hardly ever have insect or disease problems. Rarely do bothersome rats and deer show any interest.

Most alliums are perennial plants. They will typically bloom again if the species you are planting is winter hardy and the bulbs are suitable to the growing environment in your yard.

Caring for Alliums After They Flower

Allium wasted flower heads can be removed or left in situ once flowering is over. The seed heads are viewed as an intriguing decorative element by many gardeners. Depending on your environment, they may persist far into the beginning of the fall.

Large-headed alliums like Schubertii and Globemaster hardly ever produce viable seeds. Purple Sensation and drumstick alliums will reseed if the conditions are favorable. Simply remove the seed heads after the flowers have faded and before the seeds develop to prevent a carpet of tiny volunteers.

There are herbaceous alliums as well as alliums that grow from bulbs, including varieties like Millennium and Summer Beauty. These plants have a big root system and come back every year to blossom.

Alliums that emerge from bulbs require their foliage in order to generate energy for the blossoms of the next year. Therefore, it’s crucial to let these plants die back organically. The leaves may typically be removed with a simple tug once it has turned yellow and dried. Trim off the wasted blooms from herbaceous alliums with hedge shears or scissors once they have stopped blooming. This will maintain the plants’ clean appearance and might promote a second flush of blossoms.

How is allium maintained?

To add height and beauty to your spring garden, plant some allium bulbs in your October bulb planting. For tall, scattered color throughout your beds next year, scatter them among the bulbs of lilies, crocus, and some of your other favorite spring blooming bulbs. Plant seeds of the candytuft flower and other short perennial flowers once the soil has warmed up to cover the developing alliums’ foliage as it withers away after the show is finished.

In a sunny area, plant the allium bulb three times its height deep in well-draining soil. Alliums can ward off aphids, which frequently enjoy sucking on the sensitive new growth of other spring blooms. Rodents, the peach borer, and even the destructive Japanese beetle are deterred by growing alliums in the garden.

If planted in the appropriate soil and sunlight, allium maintenance is easy. The allium plant simply requires infrequent weeding, fertilizing, and watering. Both rainfall and the use of organic mulch after planting could meet these requirements. Pre-emergence organic weed blocks or mulch may reduce the need for weeding.

Many of your other growing specimens will benefit if you learn how to plant allium bulbs. You will use this gardening tip for years to come: learning how to grow alliums.

Should allium heads be removed?

Deadheading allium is mostly done to make the plants look better and stop them from self-seeding in the garden. According to White Flower Farm, common allium cultivars like the “Globemaster” (Allium cristophii x macleanii “Globemaster”; zones 6 through 10) are sterile. Since they don’t generate viable seed, deadheading is only done to enhance the appearance of the plant. Some cultivars, such the nodding onion (Allium cernuum; zones 4 to 8), self-sow so wildly that the University of Wisconsin-Madison Extension advises deadheading to stop unwanted seedlings. The fact that removing the blossom head will stop the plant from setting seed is one of the strongest justifications for deadheading allium. Instead, the bulb stores the energy from seed creation to ensure the best flowering the next year.

Alliums may be deadheaded quickly and easily. Wait until the majority of the tiny, star- or tubular-shaped flowers on the spherical umbel begin to wilt and fall off before deadheading. With a pair of tidy, sharp handheld pruners, cut the flower head off at the base as it loses its color.

Are allium bulbs safe to be left in the ground?

Taller people can need assistance when exposed. After the flowers have faded, let the plant with them until they disintegrate because they make for wonderful winter interest. Some gardeners collect the seedheads and dry them so they can be used as home decor.

Allium bulbs can stay in the garden for multiple seasons. When planting new plants, try to keep in mind where you already put bulbs to prevent damaging those areas.

How to propagate alliums

In a few years, allium bulbs will grow in number. You may occasionally see the white bulbs being pushed out of the ground. Carefully pull the bulbs and gently peel out the offsets in late autumn or very early spring to replant them directly into the ground.

Allium can be grown from seed by leaving the flowerheads on the plant and harvesting the ripe seed to sow right away. Keep in mind that starting alliums from seed requires patience because it takes years to produce a flowering plant.

Growing alliums: pests and problem solving

A fungus called allium white rot prevents the growth of other alliums and onions. Clear and burn the infected plant material, and stay away from growing alliums in the same spot for at least five years, to prevent recurring infections.

Alliums have a tendency to outgrow their surroundings. Learn how to control the amount of alliums growing in a border in this Gardeners’ World video:

how do you dry alliums?

Pick off seedheads that are starting to fade and store them for a few months in a cold, dry place, such a shed or cellar. To use as Christmas decorations, I like to dry my seedheads and then spray-paint them silver.

are alliums edible?

Since they are all members of the allium family, onions, leeks, and garlic are often consumed foods. Alliums are theoretically edible, but beware eating any that are designed to be aesthetic garden plants because they may have been chemically treated.

are alliums good for bees?

In the spring, bees and other pollinators are all over our alliums. Our neighborhood beekeeper also claims that the honey doesn’t taste oniony.

do alliums need staking?

Even the tallest alliums won’t need staking since their sturdy stems can hold them if they are planted deeply enough in full sun (so they don’t extend toward the light) and in a sheltered location (so they don’t blow over in the wind).

Are allium bulbs formed from the seeds?

The growing requirements for these relatives of common onions are the same whether you are growing alliums for their eye-catching, globular flowers, like the Star of Persia (Allium christophii or A. albopilosum), or for their flavorful, pungent bulbs, like leeks (A. ameloprasum) or chives (A. schoenoprasum). Depending on the variety, both types of alliums can be grown in USDA hardiness zones 3 to 11, producing edible bulbs or blossoms in the spring, summer, or fall before withering away in the winter and regrowing the following year.

What happened to my alliums this year?

Although alliums can suffer in a drought, they do best in well-draining soil (it is a good idea to add some grit when planting bulbs to ensure proper soil drainage around the bulbs).

In the Spring and Summer, the allium may not flower or give a meager show of flowers if conditions are too dry.

Alliums store energy for the following year’s blossoms in their bulbs during the fall, thus persistent dry weather during this time might also hinder a strong flower show.

The most of the year, alliums require little maintenance, but if there is a severe drought in the spring, summer, or fall, give the soil a good soak once a week to make sure the bulbs can access the moisture when needed.

Watering shouldn’t be done in the winter because the bulb is dormant and too much moisture can cause decay.

Alliums in pots are typically more vulnerable to drought than bulbs placed along garden borders. In order to encourage flowering in the spring, water the bulbs once a week consistently if there has been dry weather.

Key Takeaways:

  • Alliums typically fail to bloom because the bulb is immature, planted too shallowly, or planted at the incorrect time of year. Alliums can also be prevented from flowering by drought, lack of sunlight, and soggy soil.
  • To have enough energy to flower, alliums need to be planted in stony, well-draining soil and be grown in full sun.
  • Manure-amended soil and soil that has received nitrogen fertilizer frequently encourage the growth of foliage at the expense of flowering plants.
  • In the late Summer and early Fall, pruning the foliage too soon while it is still green can stop the allium from providing the bulb with nutrition, moisture, and energy for the upcoming flowering season. Once the foliage becomes brown, only trim it back.