GardenSMART Therese Ciesinski
Alliums, or ornamental onions, seem to be enjoying their time in the spotlight. That’s fortunate, as these wacky flowers—which resemble pink, purple, or white balls on sticks—have a lot to offer. They are simple to maintain, entice butterflies and other pollinators, and repel rabbits and deer because of their unpleasant taste. The loose, spherical mounds of most perennials are contrasted by their striking outlines, and they are very attractive and intriguing. Much more room should be given to alliums in backyard gardens.
Some alliums only produce one flower per bulb, whereas “Millenium” bulbs produce numerous flowers as a clump. Flowers have a comparable spread and a height range of 12 to 18 inches.
“Millenium” was chosen, in accordance with the PPA website, because to its “late blossoming with masses of rose-purple blossoms, uniform habit with clean shining green foliage that remains appealing season-round, and for its drought tolerant constitution.”
Millennium (with a single “n”) made its debut in 2000. Mark McDonough, a horticulture expert, developed it in Massachusetts. In zones 3 to 9, it can survive.
Several other plants had petered out by the time these alliums bloom in July and August. Although they can thrive in different types of soil, sandy soil is the ideal for them. Like most bulbs, they can’t tolerate moist soil because it will make them decay. Effective drainage is crucial.
In a place with full sun, or afternoon shadow in warm climes, plant bulbs in the fall. Like with all flowering bulbs, once the blooming is over, keep the foliage on the bulb to feed it and encourage blooming the following year. Trim it in the fall. There are no severe pest or disease issues with “Millenium.”
Many alliums reseed excessively, while “Millenium” does not. It has infertile seed. To get extra plants, divide clumps in the spring or fall and plant the divisions.
Goldenrod (Solidago), Russian sage (Perovskia), or the yellow evening primrose (Oenothera fremontii ‘Shimmer’) complement “Millenium” beautifully.
Alliums come in roughly 700 different varieties, including foods like garlic, leeks, scallions, and onions. In fact, the Latin word allium signifies garlic.
The majority of ornamental onion blossoms have lengthy stems, making them suitable for cutting. But they are not a suitable choice for a nosegay because the foliage and blooms have the same smell as their onion cousins. And even though ornamental onions smell edible, they should not be consumed.
What month should alliums be planted?
Most likely, when you think of alliums, you picture those plants with the traditional round, purple flowerheads on long stalks that make borders look amazing in late spring and early summer. Alliums, however, are much more than this.
There are alliums that are white, pink, blue, and yellow. There are some alliums that resemble a fireworks display, and others that resemble knotted dreadlocks.
You can identify that alliums are related to onions, garlic, and leeks by the aroma released when you crush the foliage. This family also includes chives (Allium schoenoprasum), which have delicious leaves that may be sliced and used to salads and dips.
Alliums are a favorite of butterflies and bees, and even the dried flowerheads look lovely in the border or in floral arrangements.
When to plant allium bulbs
The greatest time to plant alliums is in mid- to late-autumn, at the same time as tulips and daffodils that bloom in the spring. Allium bulbs are resilient and can withstand harsh winter weather if they are planted in soil that drains effectively.
Some attractive alliums, like “Allium sphaerocephalon,” flower in the late summer. Most ornamental alliums bloom in the late spring and early summer.
Where to plant alliums
The majority of alliums thrive in full sun and well-drained soil. Tall alliums should be planted in a protected area to prevent the stems from blowing over in high winds. Plant purple-flowered chives (‘Allium schoenoprasum’), which appreciate afternoon shade, or yellow-flowered ‘Allium moly’ in shaded areas.
Tall alliums look great planted in broad swaths or punctuated across a border. Late-summer bloomer Allium sphaerocephalon has gorgeous wine-red flowers that stand out amid the grasses in prairie planting schemes.
Long, slender leaves on ornamental alliums fade back as the flowers emerge. To conceal the waning foliage, place allium bulbs under other low-growing plants.
Planting allium bulbs
- Remove any weeds by turning the dirt over. Dig in leaf mold or compost instead of using manure on heavy soil as this can change the soil’s pH level. Alliums thrive in soil with a pH that is neutral.
- Make a hole that is roughly four times the bulb’s depth.
- Put a bulb in the opening with the roots pointing down.
- Gently compact the earth after filling the hole.
Alliums can also be grown in large pots with soil that is a mixture of grit, John Innes No. 3 compost, and multipurpose compost.
Tips on caring for alliums
- Ground-planted alliums typically don’t require irrigation.
- In the spring, alliums grown in containers will require regular watering. However, avoid letting the compost become soggy as this could lead to the bulbs rotting.
- Crushed eggshells around plants, copper tape around pots, beer traps, or wildlife-friendly slug pellets can all be used to deter slugs and snails from eating new spring leaves.
- When the plants are in bloom, spread a general-purpose fertilizer to aid in the development of the bulbs, assuring healthy flowers the following year.
- Once the leaves have withered back, remove them.
- There is no need to deadhead the flowerheads unless you choose to because they still look excellent after flowering has completed. As long as they remain in place at the border, they may be ignored.
- Put pots in a greenhouse or up against a wall of a house in the winter to shield them from the cold weather.
Growing allium bulbs from offsets
Offsets, which are little bulbs affixed to the main bulb, are produced by many allium bulbs. These can either be planted directly in the ground or split from the main bulb and placed in tiny pots to grow on. Before they have developed enough to produce flowers, it will take a number of years.
Wait until the allium plants are through flowering before using a garden fork to carefully uproot the plants and inspect the bulbs for offsets. Replant the bulbs after removing any offsets.
Best allium bulbs to plant
Alliums come in a wide variety, from large to little, with flowerheads that are rounded or exotic-looking twisted. Here is a selection of the most well-liked alliums.
- One of the most well-known alliums, Allium ‘Purple Sensation’ has the traditional deep purple spherical flowerheads on long, robust stalks. 1 m (3.5 ft) high.
- Large circular purple flowerheads up to 15 cm (6 in) across on robust stems that are 80 cm (3 ft) tall characterize Allium ‘Globemaster’.
- As its name suggests, Allium giganteum is a true giant with dense, spherical purple flowerheads on stems up to 1.8 meters (6 feet) tall.
How is Millennium allium planted?
A sizable genus of culinary and decorative plants, Allium (Ornamental Onion), has deep green foliage and good deer and rabbit resistance.
- Late spring/early summer bloomers that go dormant in the summer are known as bulbs.
- Early-fall bloomers that bloom in the late summer or early fall, such as “Millennium,” are not bulbous and develop rapidly in the spring and summer.
- Plant in soil that receives full to partial light, including clay. Use typical mulch components like bark, pine needles, or gravel to cover the ground.
- Once grown, allium loves dry to moderately damp soil.
- Cut bulb-type plants down to the ground after the summer foliage starts to turn yellow. In the fall, cut non-bulb types to the ground.
- Apply a mild fertilizer in the fall, such as compost or Yum Yum Mix.
For advice on taking care of your plants once you receive them, as well as planting instructions for perennials, spring-planted bulbs, fall-planted bulbs, cacti & succulents, Xeric Plants, and more, view more planting guides or download our comprehensive planting guide.
Your order will be confirmed by email as soon as it is placed. The day your order ships, you will get a second email letting you know how it was delivered. Some perennials are sent in pots, while others are shipped as peat-wrapped perennial roots. How that item will ship is described in the ‘Plant Information’ section. All perennials and bulbs planted in the spring are fully guaranteed and shipped in shipping-friendly packaging. Please read and adhere to the included instructions as soon as you receive.
How late can allium bulbs be planted?
Yes! Alliums are annual plants that grow again year after year. Due of their extreme cold tolerance, they can endure most zones’ winters.
Alliums planted in the spring will still blossom, yes. Although the blossoms won’t be quite as big, they will return the next year in full force.
Allium may only grow as foliar growth, with no blooms, or not at all, if you plant it too deeply. To ensure the best growth and lessen the possibility of shallow bulbs being dug up by animals, try to put allium 4 inches beneath the soil surface.
The spring is not the time to transplant allium bulbs. Wait until the end of the summer when the foliage begins to turn yellow so that the plant will be in a dormant state and not be concentrating on new growth. It will be difficult to locate the bulbs if you wait until the stems totally wilt.
Does Millennium allium reproduce itself?
Over the years, the Perennial Plant Association’s Perennial of the Year program has produced some absolutely amazing plants. Nearly all previous winners in the category of perennials for temperate climates have gone on to become classics. You only need to consider a few previous winners, such as the “Jack Frost” brunnera (Brunnera macrophylla “Jack Frost,” 2012), the “Rozanne” geranium (Geranium “Gerwat,” 2008), the “Karl Foerster” feather reed grass (Calamagrostis x acutiflora “Karl Foerster,” 2001), or the “Goldsturm” coneflower (Rudbeck Many seasoned gardeners would quickly recognize the names, and even if you don’t, chances are good that you cultivate them in your garden. They are all around us!
And with the 2018 champion, Allium “Millenium,” that is most likely what will take place. This plant, created by allium expert Mark McDonough, has it all: beauty, simplicity of maintenance, wide availability, and even delicious flowers and leaves.
With more than 750 species spread across the northern hemisphere, the genus Allium is incredibly diverse. There are several spring-flowering decorative bulbs, such as gigantic onion (A. giganteum), with its enormous globe of purple flowers. Edible variants include onions (A. cepa), garlic (A. sativum), and leeks (Allium ampeloprasum). But because ‘Millenium’ doesn’t develop a true bulb but rather a dense clump of leaves with fibrous roots, it is more closely linked to its smaller cousin, chives (A. schoenoprasum).
“Millennium” has a lengthy shelf life. Before the flowers start to bloom in July, its erect, dark green leaves form a lovely tuft of green in the earliest spring, resembling an ornamental grass. The flowers, which are small purple-pink balls with a diameter of approximately 2 inches (5 cm), are delicately perfumed and bloom for about a month in the middle of the summer. They don’t smell like onions, but if you damage some leaf, it does.
Bees, butterflies, and other pollinating insects are drawn to the flowers, but mammalian herbivores like deer and rabbits stay away due to the foliage’s mild repulsiveness. It also doesn’t appear to be prone to insect infestations. There are no unwanted seedlings and no chance of the plant becoming invasive because the blossoms are almost sterile.
‘Millennium’ reaches heights of 16 to 20 inches (40 to 50 cm) and diameters of 12 to 18 inches (30 and 45 cm). Multiplying by division is simple, and you may do it in the spring or the fall.
Allium breeder Mark McDonough from Massachusetts has been a devoted collector for almost 40 years. He makes dozens of controlled crosses every year and has thousands of species and cultivars in his collection. However, alliums readily cross-pollinate, producing their own hybrids, and “Millenium” is one of the self-sown hybrids produced by some allium hanky-panky. McDonough is able to identify genes from A. nutans and A. lusitanicum in “Millenium,” but he is unable to identify the plant’s true progenitors.
As its name implies, “Millenium” was introduced in 2000 and has since achieved tremendous popularity, ranking among the best-selling ornamental alliums in the world (though it is occasionally misspelled “Millennium”). In regions where it can be grown, you should be able to find it in any garden center. If not, a fast search on the Internet will point you to mail order suppliers.
Allium ‘Millenium’ should be planted in full sun and moderately rich, well-drained soil. You should cultivate it in a container or raised bed if your soil is thick clay or wet. Once established, “Millenium” is highly drought-tolerant and forms a wonderful cut flower. It is a hardy plant for temperate regions with chilly to cold winters, ranging from zone 3 to around 8. (Some texts mention it as hardy only from zone 5 and up, but I can attest that it thrives in zone 3 just fine.)
Alliums can I plant in January?
You might think that your days of planting bulbs are finished after the first frost or snowfall. But you can plant bulbs as long as the ground is usable! If you can dig a hole deep enough to plant, you can plant bulbs as late as January.
ALLIUM PLANTING GUIDE
The allium family includes the chives in your herb garden, which are little, fluffy purple balls that bees and butterflies adore. Alliums used as ornaments, however, are anything but tiny. Big drama is what these enormous globes on tall stems are all about in your landscape. Alliums are a great choice if you are growing bulbs with kids since they enjoy the fact that when these blooms bloom, they frequently tower over them.
Garden & Container Planting
Alliums require a cold spell to establish their roots and get ready for spring, just like other flower bulbs do. So it’s time to start planting as soon as the first chill of fall appears in the air.
Although flower bulbs are hardy and simple to grow, they detest getting their feet wet since they can quickly decay if left to “bathe” in water. Therefore, avoid at all costs moist soil. this refers to locations where puddles are still visible 5–6 hours after a downpour. You can also improve possibly wet soil by incorporating organic material like peat, bark, or manure. The same motto applies when planting bulbs in containers: drainage, drainage, and more drainage. Purchase a container that has at least a few drainage holes at the bottom.
Because alliums require a lot of light to flourish, locations with less than full sun are not suitable.
Alliums must be buried deeply enough so that changes in the temperature above ground—either too warm or too cold—won’t influence them. Because containers can’t protect bulbs as well as mother earth can, it may be preferable to let your containers spend the winter indoors in a cool, dark, well-ventilated area where the temperature won’t rise above 60 degrees Fahrenheit, such as an unheated basement or garage, if you live in one of the hardiness zones 3 to 7.
The bulb is placed at the bottom of the hole with its sharp end facing up, and a hole three times as deep as the bulb’s height is dug to determine the optimal depth. When competing for nutrients with other bulbs, alliums perform worse, therefore it’s best to space them 6 to 8 inches apart.
After planting, it’s crucial to give the bulbs plenty of water to help them settle and develop roots rapidly, but after that, you won’t need to water them again. All that’s left to do is wait patiently for spring to come and surprise you with the fruits of your labor and for winter to work its magic underground.
Alliums don’t typically need watering during the flowering season, but you can water them if there hasn’t been any rain for three to five days.
Don’t trim the foliage of alliums right away after they have stopped flowering; through photosynthesis, the leaves will produce the nutrition the bulb needs for its subsequent growing season. The leaves will naturally turn yellow and die back after a few weeks, at which point you can remove it. The bulb will now enter dormancy and won’t require watering again until the following spring.
How to plant alliums in your garden:
- Wait till the soil is 60°F or colder before planting. This will happen around September or October in the North and October or November in the South.
- Choose a location in your garden that has soil that drains properly and receives full sun.
- The allium bulbs should be planted with their pointed ends facing up, 4 to 8 inches deep, and 6 to 8 inches apart.
- once, and then wait until spring.
- Don’t remove the leaf from alliums after they bloom. Remove it once it has entirely withered and become yellow.
How to plant alliums in containers:
- Wait until the soil temperature is at least 60 degrees Fahrenheit and the weather is chilly. This will happen around September or October in the North and October or November in the South.
- Choose a location in your garden that receives direct sun.
- Find a container with good drainage, fill it with loose soil, and make sure that water won’t collect and pool at the bottom.
- The allium bulbs should be buried in the ground with their pointed ends facing up, 4 to 8 inches deep, and 6 to 8 inches apart. You can try putting the bulbs closer together since containers frequently have a small amount of room, but make sure they never touch.
- If you reside in hardiness zones 3–7, you can water well once and wait until spring, or you can bring the containers inside and let them spend the winter in a cool place like an unheated garage or basement.
Special effects
You can choose the extremely regulated technique if you prefer order and cleanliness or if you want to maximize the wow-factor alliums can provide to your garden or container. Grow your alliums in straight rows with roughly 10 bulbs spaced closely apart (you might want to add some fertilizer to the soil to make sure they still get all the nutrients they need). Growing a row of 10 taller alliums, like Purple Sensation, behind a row of 10 slightly shorter ones, like Azureum, can produce an even more dramatic effect.