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Giant ornamental bulb with white flowers
Amaryllidaceae
Ornamental fall-planted bulb
White Giant ornamental onion
Allium stipitatum ‘White Giant’
Product code : ALLIUM-WHITE-GIANT
White Giant is an architectural 120 cm Allium stipitatum carrying a dense spherical umbel 20 cm across, composed of pure white star-shaped flowers with green centres. The Van Noort package contains one size 18/20 bulb for fall planting, set 20 cm deep and about 30 cm from neighbours. Hardy in Zones 4 to 10, it prefers sun or light partial shade and sharply drained soil. The display attracts pollinators and suits fresh or dried bouquets. Its bright colour remains highly visible from across the garden. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs.
- Quantity
- 1 bulb
- Exposure
- Full sun to light partial shade
- Life cycle
- Naturalizing bulbous perennial with summer dormancy
- Hardiness
- Zones 4 to 10
Discover the plant
Common nameWhite Giant ornamental onion
FamilyAmaryllidaceae
GenusAllium
Speciesstipitatum
CultivarWhite Giant
TypeGiant ornamental bulb with white flowers
Botanical nameAllium stipitatum ‘White Giant’
‘White Giant’ ornamental onion (Allium stipitatum ‘White Giant’) creates a luminous vertical silhouette reaching about 120 cm. Its sturdy leafless green stem carries a dense spherical early-summer umbel roughly 20 cm across, composed of hundreds of pure white star-shaped florets with small green centres. Broad green basal foliage often begins fading as the display reaches its peak. This large white selection provides crisp architectural presence in borders and catches morning or evening light especially well, remaining clearly visible against dark foliage. Good drainage remains essential to protect the bulb during rainy periods.
The Van Noort package contains one size 18/20 bulb. Plant it in fall, pointed end upward, 20 cm deep and about 30 cm from neighbouring plants. Choose full sun or light partial shade in fertile, loose, sharply drained soil. Incorporate fine grit into clay to prevent standing water. Water after planting, then moderately whenever the surface dries during active growth. Discreet support may protect the stem in a very windy garden. After flowering, retain every leaf until completely yellow so it can replenish the bulb for the following season. Good drainage remains essential to protect the bulb during rainy periods.
Place White Giant in the middle or back of a border among peonies, salvias, catmint, irises, and grasses that later conceal its fading foliage. The white globe contrasts elegantly with purple Allium, dark leaves, and pastel flowers. One bulb already creates a focal point; repeat several widely spaced plants to rhythmically structure a long border. Flowers attract bees, bumblebees, and butterflies and cut well for fresh or dried bouquets. Deer generally avoid Allium. The plant remains ornamental and may be toxic to pets if eaten, so store unplanted bulbs securely.
Planting guide
Plant well.Grow beautifully.
Planting depth
200 mm
Spacing / density
30 cm (12 in) between bulbs
Best planting time
Fall
Propagation
Division of offsets in fall during dormancy
Growing method
Plant White Giant in fall, ideally four to six weeks before the ground freezes solid. Choose full sun or light partial shade where the 120 cm stem remains visible without obstructing a path. Loosen the soil to at least 35 cm and incorporate mature compost. In clay, add fine grit and plant on a slight mound so winter water drains quickly. Set the size 18/20 bulb pointed end upward, 20 cm deep and about 30 cm from neighbouring plants. Water after planting. In spring, maintain moderate moisture only when the surface dries. Install discreet support before opening if the site is windy. The 10-to-15-cm white umbel appears in early summer. Cut it for a bouquet when most florets are open or let it dry on the plant. Retain every leaf until completely yellow, then reduce irrigation during dormancy. Divide healthy offsets in fall whenever the clump becomes crowded. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs. The flowers attract pollinators and also make elegant fresh bouquets. Grouped planting creates a bright architectural effect throughout the garden border.
Soil and care
The right care,at the right time.
Soil pH
Acid to alkaline
Minimum temperature
-34°C (-30°F)
Care level
Easy
Watering
Water thoroughly immediately after planting, then let fall and spring rainfall supply most of the moisture. During active growth, irrigate only when the top five centimetres of soil feel dry. Apply water directly to the soil rather than over the foliage. Reduce watering gradually after flowering and stop once the leaves turn yellow. In containers, check moisture more often, but always empty the saucer so the bulbs never remain waterlogged.
Soil type
White Giant grows well in loose, fertile, sharply drained soil, whether loamy, sandy, improved clay, or slightly chalky. Incorporate mature compost without creating an overly rich pocket beneath the bulb. In heavy ground, mix in fine grit and plant on a slight mound so winter water drains away. Slightly acidic, neutral, or alkaline soil is suitable, provided its structure remains open and the bulb never sits in water.
Fertilization
In early spring, spread a thin layer of mature compost around emerging shoots without covering their bases. In poor soil, add a balanced slow-release granular fertilizer at the lowest recommended rate. Avoid high-nitrogen formulas, which encourage soft foliage at the expense of flowers. After bloom, allow the leaves to replenish the bulb naturally; no summer feeding is needed while the plant is dormant.
Moisture
Maintain even but moderate moisture during rooting and spring growth. Soil should stay lightly fresh without becoming saturated, especially during cold rainy weather. Good air circulation helps reduce downy mildew. Once the foliage disappears in summer, keep the dormant bulb considerably drier. Avoid thick wet mulch against the crown and frequent irrigation during dormancy, since both conditions encourage bulb and root diseases.
Seasonal care
In fall, plant the bulbs 20 cm deep and mark their position so they are not disturbed. Protect new plantings with a light mulch after the soil cools, without burying the crown heavily. In late winter, remove excess mulch and confirm that water drains freely. During spring, weed carefully around emerging shoots, add a little compost, and water only if conditions become dry. Place discreet supports before flowers open when the garden is windy, although sturdy stems normally stand unaided. After bloom, remove spent heads for a tidy appearance or retain a few for their sculptural seed-head outline. Never tie the leaves; let them yellow and dry completely because they rebuild the bulb’s reserves. Reduce watering sharply during summer dormancy. The following fall, lift crowded clumps, separate healthy offsets, and replant them immediately. Watch for pure white rot, downy mildew, slugs, and onion-related pests; remove affected tissue promptly and avoid planting another Allium in contaminated ground. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs. The flowers attract pollinators and also make elegant fresh bouquets. Grouped planting creates a bright architectural effect throughout the garden border. After flowering, let the foliage yellow completely before removing it. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs.
Container growing
A garden,within reach.
Recommended pot size
At least 50 cm (20 in) wide and 40 cm (16 in) deep
Grow White Giant in a heavy container at least 50 cm wide and 60 cm deep, with numerous drainage holes. Fill it with fertile, light potting mix amended with mature compost and fine grit. Set the two size 18/20 bulbs pointed end upward, 20 cm deep, retaining about 30 cm between them. Place the pot in full sun or very bright partial shade against a wall or in a corner protected from gusts. Water after planting, then regularly whenever the surface dries during spring and early summer. Install strong support as soon as stems emerge because 120 cm stalks and 15 cm umbels catch considerable wind. Let foliage yellow completely after bloom and reduce watering. For a Quebec winter, insulate the sides, temporarily bury the container, or move it to an unheated sheltered outdoor space. In spring, inspect drainage, replace the upper layer of mix, and feed moderately. Divide bulbs whenever the container becomes crowded. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs. The flowers attract pollinators and also make elegant fresh bouquets. Grouped planting creates a bright architectural effect throughout the garden border.
Bloom and dimensions
Its place,in your garden.
Mature height
120 cm (48 in)
Width / spread
20 to 30 cm (8 to 12 in)
Flower color
Pure white with small green centres
Foliage color
Green
Foliage type
Deciduous herbaceous broad green strap-shaped foliage
Growth rate
Moderate
Growth habit
Upright, tall, and architectural
Fragrance
Fragrant flowers
Bloom period
From late spring into early summer, generally June to July in Quebec, White Giant carries a dense spherical 10-to-15-cm umbel on a green stem about 120 cm tall. Hundreds of pure white star-shaped florets with small green centres open progressively and attract bees, bumblebees, and butterflies. The globe remains luminous for several weeks. After bloom, its dried head retains a graphic silhouette that stays decorative in the border or in arrangements. for lasting seasonal interest.
Garden associations
In goodcompany.
Companion plants
Pair White Giant with white salvias, blue catmint, peonies, irises, hardy geraniums, and fine-textured grasses. These plants share its preference for sun and drained soil while gracefully hiding yellowing Allium foliage. Late tulips extend the spring sequence, whereas coneflowers and black-eyed Susans continue the display in summer. Maintain enough distance from moisture-demanding perennials, however, and avoid dense groundcovers that trap humidity around the bulbs or restrict air circulation. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs.
Frequently asked questions
Your questions,answered.
How deep should White Giant bulbs be planted?
Plant each bulb about 20 cm deep, measured from the bulb’s base to the soil surface, with the pointed end facing upward. Leave roughly 30 cm between bulbs to provide room for roots and good air movement. In clay soil, loosen the ground more deeply and mix in fine grit so water cannot collect beneath the bulb. Water once after planting to settle the soil, then allow fall rainfall to support rooting. Mark the position so emerging shoots are not damaged during spring cleanup or cultivation. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs.
Will White Giant return every year in Quebec?
Yes. White Giant is a perennial bulb suited approximately to zones 4 through 10 when grown in sharply drained soil. In Quebec, winter survival depends mainly on preventing standing water around the bulb. Plant at the recommended depth, apply only a light mulch after the soil cools, and remove excess mulch in spring. Always let the foliage yellow completely after flowering so it can replenish the bulb. In a container, insulate the sides against rapid freeze-thaw cycles without moving the pot into a heated room, because the bulb requires a cold dormant period. Good drainage remains essential to protect the bulb during rainy periods.
Why is my White Giant Allium not flowering?
Poor flowering often results from insufficient sun, waterlogged soil, shallow planting, or foliage removed too early during the previous year. Give the plant several hours of direct sunlight, ensure rapid drainage, and retain every leaf until it yellows naturally. Avoid high-nitrogen fertilizer, which mainly encourages foliage. If the clump has become crowded, lift it in fall, separate healthy offsets, and replant them 20 cm deep. Small offsets may require several growing seasons before reaching flowering size, while mature bulbs should bloom reliably under bright, well-drained conditions. Good drainage remains essential to protect the bulb during rainy periods. A light mulch limits weeds without trapping excessive moisture around bulbs.
Can White Giant be grown in a container?
Yes, although its height requires a very large, stable container at least 50 cm wide and 60 cm deep. Use fertile, light, sharply drained potting mix, then set the one bulb 20 cm deep and about 30 cm apart. Position the pot in full sun against a sheltered wall and install strong stakes as soon as stems emerge. Water when the surface dries without leaving water in the saucer. For a Quebec winter, insulate the sides or temporarily bury the container while preserving the cold dormant period needed for flowering. Good drainage remains essential to protect the bulb during rainy periods.
When should White Giant flowers and foliage be cut?
Cut umbels for bouquets when most of the small flowers have opened. In the garden, remove spent heads if you want to prevent seedlings, or retain them for their sculptural appearance. Foliage requires a different rule: never cut, tie, or braid it while it remains green. At that stage it is producing the reserves needed for next year’s flowers. Wait until every leaf is completely yellow and dry before removing it easily. At the same time, reduce watering gradually so the bulb enters summer dormancy in comparatively dry soil. Good drainage remains essential to protect the bulb during rainy periods.
Wildlife and pets
Life,around your plants.
Reported toxicity
Yes
Supporting wildlife
The many nectar-bearing star-shaped flowers mainly attract honeybees, native bees, bumblebees, and hoverflies in late spring. Butterflies may also visit the broad umbels in calm weather. The plant therefore supports pollinators without being especially attractive to birds or hummingbirds. Avoid insecticides while flowers are open so these beneficial visitors can forage safely.
For planting your bulbs
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