Alliums are flowering plants that grow from bulbs planted in the ground. They can live for up to four years after planting. Alliums have a long flowering season, blooming for several weeks to bridge the transition from spring to summer.
Their puffy, pompom-like flowers come in shades of purple, pink and white, attracting lots of bees. Alliums look best when planted in large groupings. To know more about allium care and plantation keep reading the article below.
Choosing The Right Allium Variety
Alliums come in many colors, shapes, and sizes to suit any garden. Before planting, decide if you want compact alliums for pots or tall, showy varieties for borders. The flower colors range from classic purple to white, yellow, and pink. Some alliums have big, round blooms while others have oval, drumstick shapes.
Tall alliums like 'Purple Sensation' and 'Globemaster' make striking accents planted in small groups through the garden. Their large purple spheres stand out beautifully.
For a more natural look, try egg-shaped drumstick alliums scattered through wildflower plantings. They blend nicely with meadow grasses and flowers.
Smaller types like pure white 'Mt. Everest' work well in containers on patios and decks. Their size allows you to appreciate the intricate details up close. No matter which you choose, alliums add long-lasting interest and texture to any spring or summer garden.
Alliums thrive in sunny spots and well-drained soil. They aren't too picky about soil type. When planting in borders, put taller varieties toward the back and shorter types in front. Alliums make great container plants, but their strap-like leaves can look messy after blooming.
Alliums sprout leaves before the showy flowers emerge. This leafy growth looks best in the middle of borders where other plants can hide it as it fades while the allium blooms steal the spotlight. To camouflage the dying foliage, plant alliums among ornamental grasses and spreading perennials.
For a bold, dramatic look, plant many alliums in flowing drifts through your borders. Or you can naturalize them by planting them in drifts throughout your lawn for punctuations of color. Their easygoing nature, unique shapes, and vibrant colors make alliums a valuable addition to any sunny garden space.
When To Plant Allium
Alliums bulbs need a cold, dormant period to bloom properly. That's why they must be planted in fall. In spring, they send up leaves and flowers, bloom beautifully, then die back and go dormant underground for the summer. To prevent bulb rot, plant them in well-draining soils like rock gardens or areas that don't stay soggy.
Many gardeners love the big, round allium bloomers in spring like:
Globemaster
Gladiator
Purple Sensation
The giant 8-inch flower heads of Allium giganteum
But there are many other delightful allium varieties too. Some have explosive, fireworks shapes like tumbleweed allium or Star of Persia. Low-growers like Ivory Queen Turkestan onion hug the ground. And drumstick alliums, with their slender stems and oval flower clusters, add whimsical accents.
No matter which you choose, these cold-hardy, easy-care bulbs provide unique colors, forms, and textures to enliven spring gardens.
When planting allium bulbs in the fall, follow these tips for best results:
1. Dig a planting hole at least 4 times deeper than the bulb size
For example, a 2-inch bulb needs at least a 8-inch deep hole
It's better to plant too deep rather than too shallow
2. Place only one allium bulb in each planting hole
If you want a more natural, drifting look:
Space smaller allium varieties 7-10 inches apart
Space taller, larger allium bulbs around 20 inches apart
Wider spacing reduces competition and allows room for mature sizes
3. Set the bulb in the hole with the pointed end facing up
4. Backfill with soil and gently firm the soil over the bulbs
5. If the soil is already moist, no need to water after planting
But in dry fall conditions, water the area thoroughly
6. In early spring when allium foliage first emerges:
Apply a balanced granular fertilizer around the plants
This gives bulbs a nutritional boost for lush growth and bigger blooms
Planting alliums at the proper depth with good spacing mimics their natural growing conditions. The deep planting insulates bulbs through winter, while proper air and soil space allows robust development.
Ornamental onion plant are quirky little bulbs that produce eye-catching spherical flower clusters atop tall, slim stems. While their unusual blooms look exotic, these plants are remarkably low-maintenance once you provide the right growing conditions.
The two critical requirements are sunlight and well-draining soil:
Give them a spot that receives at least 6-8 hours of direct sun exposure daily. Full sun is ideal for promoting the best flowering and overall plant vigor.
Prepare the planting area with soil that drains freely to prevent the bulbs from rotting. Incorporate plenty of compost, peat moss, or other organic matter to create a
loose, well-aerated soil mix that won't become compacted and waterlogged.
Once you've addressed those basics, here are a few more easy guidelines:
Water infrequently, only when the top few inches of soil are becoming dry. Apply water deeply but infrequently rather than light, frequent waterings.
In late summer, provide an application of a balanced, slow-release fertilizer if your garden soil is lacking nutrients. This gives the bulbs an energy boost as they prepare for their flowering period.
After the foliage dies back naturally in fall, remove the dead leaves by cutting them off at the base. This keeps things tidy over winter.
Alliums prefer a slightly acidic soil in the 5.5-6.5 pH range. However, good drainage is far more crucial than precise pH levels.
With a sunny site and well-draining, lightly fertilized soil, these unique bulbs make virtually care-free additions to gardens. Follow those simple guidelines, and you'll be rewarded with their showy pom-pom blooms with very little effort required.
Pruning Alliums
Alliums are non-repeating bloomers, meaning they only flower once per season. After their showy blooms have faded, pruning is recommended:
Trim the flower stalks all the way down to the base once the flowers are spent. This redirects the plant's energy away from seed production and back into the bulb for next year's growth and flowering.
However, many gardeners choose to leave the unique dried flower heads standing through winter. The interesting ornamental shape and texture they provide makes for fantastic winter interest in the garden.
If leaving dried heads, be sure to remove the surrounding dead foliage by cutting it off at the base to keep things tidy.
Propagating Alliums
These bulbs multiply very gradually by producing small offset bulbs. Propagation is best done through division in either early spring or late fall.
For Bulb-Forming Types:
Wait until after the plants have flowered and the foliage starts dying back.
Carefully dig up and lift the bulbs from the ground.
Gently break apart and remove any offsets from the main bulb or flower stem.
Replant the offsets immediately at a depth of 2-3 times their diameter.
Water well after transplanting.
Be patient - the new offsets may not sprout growth until the following spring!
For Rhizome-Forming Types:
You can lift and divide the spreading rhizome clumps any time they become overcrowded.
No need to wait for the center to die out first. Simply separate the rhizome sections and transplant.
Propagating alliums takes some patience as they multiply slowly. But this method allows you to gradually expand your allium displays over time from just a few starter bulbs.
Ornamental alliums have a terrific resistance to many pests and diseases thanks to their strong smell and taste compounds. This odor serves as a natural deterrent to deer, rabbits, and other mammalian pests that avoid nibbling on them.
Their disease resistance is another major advantage for low-maintenance gardeners.
Fungal Issues
While flowering alliums are relatively unbothered by most fungal pathogens, they can occasionally fall victim to:
Downy mildew - Causes yellowish patches on leaves and white fungal growth
Bulb/root rots - Excess moisture leads to bulb decay and plant collapse
Prevent fungal problems by planting alliums in well-draining soil amended with compost or other organic matter. Provide good spacing and avoid overcrowding plants. Most importantly, allow the soil to dry moderately between waterings. If issues arise, remove and discard any infected bulbs/plants promptly.
Insect Pests
Given their pungent aroma, alliums have few insect pests to deal with. The main insects to watch for are:
Slugs and snails - These moisture-loving pests can chew on foliage
Allium leaf miners - The larvae of these flies tunnel inside the leaves, causing streaking damage
Preventive Measures
Plant alliums in well-draining soil amended with compost
Allow soil to dry between waterings
Provide good air circulation around plants
Remove any diseased plant debris promptly
While unsightly, leaf damage is mainly just a cosmetic issue since alliums are grown for their showy flowers, not foliage. Good cultural practices like proper spacing and cleaning up debris help minimize pest issues.
With well-draining soil, adequate airflow, and prompt removal of any affected plants, ornamental alliums are generally quite resistant to most pests and diseases. Their natural defenses make them nearly foolproof for easy, low-maintenance planting.
Popular Allium Varieties
In addition to their easy care, one of the greatest joys of growing alliums is the amazing variety of flower forms available. From drumstick shapes to explosive firework heads, these ornamental onions offer unique textures and colors to liven up any garden.
Drumstick Allium (A. sphaerocephalon)
Compact 12-16 inch stems topped by 1-inch oval flower heads
Blooms emerge olive-green in early summer, aging to rusty-red pom-poms
Let them naturalize through borders and plantings for delightful accents
Corkscrew Allium (A. senescens glaucum)
Forms small, slowly-spreading ornamental clumps from rhizomes
Bluish-green foliage puts on a twisting, spiraling show in spring
Topped by 2-inch lavender sphere flowers in mid to late summer
Japanese Onion (A. thunbergii)
Low-growing with loose, dandelion-puff blooms in shades of pink or white
Cultivars like 'Ozawa' have larger 4-6 inch purple pom-pom heads
Blooms in early fall when most other alliums are done
Rhizomatous for gradual spreading rather than bulbs
Nodding Onion (A. cernuum)
Among the tallest alliums at 2-3 feet high with arching, floppy stems
Loose mop-headed blooms in shades of pink, lilac and violet
Reliable performer, even in partially shaded areas
Schubert Allium (A. schubertii)
Explosive firework-shaped 9-12 inch flower heads
Deep reddish-purple globes retain fantastic shape as they mature
Also called "tumbleweed onion" for dried seed heads that blow away
Stunning when massed, one of the largest and boldest allium varieties
From tiny spheres to giant explosions, ornamental alliums offer an incredible range of flower shapes, colors and bloom times to delight through every seasons.
