The giganteum species of decorative onions is the tallest of the many Allium species. The plant can spread 1 1/2 to 2 feet and reach heights of 3 to 5 feet. Every three to four years, divide and replant bulbs.
Flowering & Fragrance
From May through June, the colorful, fragrant, purple blossoms are in bloom. Three weeks or so are considered the bloom period.
Early in the spring, tall, sturdy stems (3 to 4 inches high) appear from the middle of the basal rosette.
Large, eye-catching, spherical clusters of purple flowers start to bloom by late spring. These amazing flower globes are about the size of a softball.
Foliage Of Allium Giganteum
The foliage develops as a greenish gray basal rosette. The strap-shaped, fragrant leaves are about 18 inches long.
The gigantic allium plant’s stems and leaves smell like onions, although it is not a food plant. It is the only Allium plant cultivated for its enormous blossoms.
Lighting For Giant Allium Bulbs
This Allium bulb can survive in USDA hardiness zones 5 through 8 in the US. The Giant Allium has to be fully exposed to the sun and shielded from strong gusts.
Watering and Feeding Requirements
Allium simply needs a little bit of irrigation. After planting, soak the ground. When planting, use a fertilizer for flowering bulbs. You won’t need to fertilize once more.
Once established, the plants can withstand drought. You may not need to water at all if you often have rain. Never let plants stand in water for too long; doing so will cause the bulbs to decay.
Soil Requirements & Transplanting
Allium ornamental blooms thrive when:
- kept out of the way of powerful winds
- grown in direct sunlight
- planted in rich, draining soil
Wait until the end of the growing season, after the foliage has died back, to transplant or move plants.
Ornamental Onion Grooming & Maintenance:
Following flowering, plants lose their leaves, leaving only their tall, upright stems and pom-pom blossoms. To keep the stem from falling over, you might need to stake it.
How is Allium giganteum grown?
The show-stopping Giant Allium (Allium giganteum) produces massive, 6–8-inch flower heads with a profusion of star-shaped, lilac-colored blossoms on robust stalks that reach a height of 4-5 feet. Long-blooming Giant Allium blossoms are wonderful for drying or cutting for arrangements. Place towards the back of a border and fill with perennials, giving these big bulbs lots of freedom to expand. Giant Allium (Persian Onion), which flowers in late spring to early summer, is resistant to deer. Grow in dry to ordinary, well-drained soil, in full sun to partial shade. After planting, thoroughly water.
Good For Cut Flowers, Good For Dried Flowers, Attract Butterflies, Easy To Grow, Bee Friendly, Deer Resistant, Rabbit Resistant, Fragrant Flower / Foliage
Does Allium giganteum grow in numbers?
Under ideal conditions for growth, enormous allium bulbs will proliferate quickly, which can cause overcrowding and a loss of vigor. Fewer or smaller blooms may suggest that a bunch of established gigantic alliums needs to be divided sooner even though it usually takes several years for the bulbs to grow congested.
Alliums can be moved in the spring. The best time to raise and divide the bulbs is in late summer, when the ground has dried up and the leaves and flower stalks have entirely withered away. When the smaller, newly formed bulbs are ready, remove them and plant them in nursery pots or in a different bed.
How is Allium giganteum cared for?
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.
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.
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.
Can alliums be grown in containers?
Deep pots work nicely for the majority of alliums. You can either combine equal parts of John Innes No. 3, peat-free multi-purpose compost, and horticultural grit, or use a nice peat-free general purpose potting compost. To hide the waning foliage, alliums in pots can be positioned behind other containers.
What do I do with enormous alliums when they flower?
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.
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.