The blossoms of allium plants are large, softball-sized, and purple in color. They thrive in areas that are both sunny and protected, where the wind is less likely to tear the blossoms apart. They typically bloom in the early summer under these circumstances and last for three weeks on average.
Deadhead the blossoms once the flowers have gone. However, keep the foliage in place because it needs time to naturally wither in order for the bulbs to store energy for the growth of the following season. It’s a good idea to put alliums in a bed with later flowering flowers that might disguise and obscure them because the leaves may look a touch scraggly.
Are allium bulbs replanted 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.
The duration of an allium bloom.
The ‘Jeannine’ golden onion (USDA Hardiness Zones 39) appears in late spring and only gets to be about a foot tall. A circular floret is formed by two stems of separate, star-shaped, golden yellow blooms. ‘Jeannine’ is one of my favorite plants because of how easily its supple, strap-like, blue-green leaves tuck in between the gorgeous blue flowers that bloom in the late spring to early summer. Plant at least a dozen bulbs if you want to see any type of display. ‘Jeannine’ keeps growing and will put on quite a show in a few years. This tiny golden gem will equally impress you if you enjoy seeing vast drifts of golden daffodils.
It is a shocker to move on to something that resembles a massive lollipop on a stick after viewing this average-sized garden treasure. Its name accurately describes the giant onion (Zones 59), which emerges in the late spring and grows to be towering and brash. The 4-inch-diameter blossom is a lovely lilac color, but the big leaves are a pain because they start to turn yellow even before the flowering has fully developed. This plant will require a hardy perennial to cover its wilting foliage if it is not planted at the back of a border. The blossoms of giant onions have a long flowering period and make wonderful cut flowers. Give these big bulbs plenty of room to grow when planting.
The short, squat Turkestan onion (Zones 59) blooms in late April. Being only one foot tall, this plant is right up my alley. On this onion, the broad leaves are a striking gray-green with purple flecks and a sort of reddish border. The perennial flower has a silvery-lavender hue. Do not remove the spent flower even after it has finished flowering since it dries quickly. For my daughter’s Halloween costume the year before, I spray-painted one to make a fairy wand. Try spray painting those who dare to stand out in your yard; it has a funky effect. For best results, plant Turkestan onions in groups of three or five. With “Caradonna” blue sage (Salvia nemorosa “Caradonna,” Zones 59) in the background, it makes for a striking combination.
Tumbleweed onion is a charming plant that has been cultivated since the Victorian era (Zones 49). On short stems, the rose-purple flowers start to form. The unproductive blossoms erupt, creating the appearance of pyrotechnics. The head of a tumbleweed onion is open and airy rather than being tightly packed. After flowering, the leaves disappear quickly, but the seed head will continue to look nice. When it finally drops off, it will start to roll around the garden as a tumbleweed did in the Wild West.
Waterwise bulbs keep summer rolling
There is a lot of variety among alliums that flower in the summer. Native to the northeast, the nodding onion (Zones 48) bulb. Its common name comes from the way its delicate, light pink blossoms hang down. Early in the summer, nodding onions begin to bloom, and they have a lengthy bloom time. This allium can be tucked in between perennials that bloom in the spring and summer because it is only 18 inches tall. This bulb always nods, for those who have never grown it. This is not to say that it need water.
Blue is a popular color for perennial border plantings. Zones 410’s Blue Globe Onion (Zones 410) is an outstanding blend of light and dark blues. The 24 inch tall, sphere-shaped flowers are great for cut arrangements. To create a striking contrast in color, combine this variety with the “Becky” Shasta daisy (Leucanthemumsuperbum “Becky,” Zones 58) or “Silver Moon” Stokes aster (Stokesia laevis “Silver Moon,” Zones 59), both of which have daisy-like white flowers. Avoid sprinkler systems that maintain the soil’s moisture because this bulb thrives in hot, dry conditions.
Stars of Persia is another allium with a stunning factor (Zones 58). It boasts a beautiful light amethyst globe with a 10-inch diameter, silver shadings, and green eyes. Give it room because it is a big bulb in order to utilize it to the fullest. The white hairs on the leaves give this plant its alternate name, downy onion. Although it makes a wonderful dried flower, avoid planting it in the front of the border unless you enjoy the smell of wilting foliage. Put it in back of any plant 10 inches or shorter because it is tall and requires full sun.
Round out the growing season with these colorful oddballs
Black onion is one of my favorite summer bulbs (Zones 58). Although the star-shaped flowers are white, their dark black to dark green cores provide for a striking contrast. Even finicky gardeners will adore this allium because of its strong black cores, unlike some designers who dislike the sometimes washed-out appearance of white flowers. Even after their beautiful, 4- to 6-inch-diameter flowers have finished blooming, the seed heads continue to look good for a while (for those of you nondeadheading enthusiasts). For some subtle color echoes, combine this with some of the chocolate-hued heucheras (Heuchera spp. and cvs., Zones 38) or any other dark-leaved plant.
twig-like allium (Zones 49) I believe “Instead of the type of drumstick utilized for playing, “drumstick” refers to a drumstick on a chicken. is one of my favorite summertime activities. I adore this egg-shaped bloom, which thrives in my yard and tends to naturalize. This gem keeps its vibrant color when other full-sun flowers start to fade. Compact crimson-purple flowers cover the plant. You have a simple, foolproof combination because they bloom in the middle of summer, when golden daisies are in full bloom. I adore the around three to four week bloom period, but once more, the foliage starts to turn yellow while the blooms are still gorgeous.
If you haven’t seen it, the “Hair” allium (Zones 48) appears to have grown its roots within an electrical outlet. From a purple base, each stalk sprouts numerous slender, tentacle-like green blossoms. You should pair “Hair” with anything you consider to be pretty dull since it will make you pay attention (even if you are not partial to such a weird plant).
A really cool plant is the circle onion (Zones 49). Its name comes from the corkscrew-like effect the blue-green leaves produce. The circle onion’s blossom is more appealing due to its showier foliage and richer pink flower than the species. The curly onion looks best in Japanese-style gardens; try planting it in rock gardens or at the front of the border.
Alliums are a popular flower in the fall. When most plants are starting to slow down in September, the Japanese onion known as “Ozawa” (Zones 49) begins to blossom (but it sometimes goes to frost in my cold Zone 6). The good news is that the glossy, thin foliage never looks awful because it flowers so late. On such a tiny shrub, the star-shaped purple flowers give the impression of being vast. Combine it with any of the white mums or asters that are in season at the moment.
If reading this post and seeing the spring through October array of colorful alliums hasn’t turned you into a “Alliophile, let me just remind you that this bulb is the one you need if you want to keep deer out. All season long, your garden will be lovely and free of deer.
Why fail alliums?
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.
When alliums have finished flowering, what should you do with them?
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:
When should allium bulbs 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.