Blue Globe Onion Allium caeruleum
ABOUT
Allium caeruleum, commonly known as blue globe onion, is a striking ornamental plant with a distinctive appearance. It is most well-known for its spherical clusters of small, star-shaped flowers that combine to form a tight, globe-like head. These flowers boast a vivid blue color, a shade that is somewhat rare in the plant world, adding a touch of unique charm to gardens. The blossoms sit atop tall, slender stalks which rise elegantly above the foliage. The leaves of the blue globe onion are slender, green, and grass-like, often with a slight arch, lending a soft texture to the plant's overall form. As part of the onion family, this plant shares some characteristics with its edible relatives, but it is primarily valued for its aesthetic contribution to garden spaces.
About this plant
NamesFamily
Amaryllidaceae
Synonyms
Blue Globe Onion, Blue Ornamental Onion, Blue-of-the-Heavens, Blue-flowered Garlic
Common names
Allium azureum, Allium caeruleum var. bulbilliferum, Allium caesium, Allium jajlae.
ToxicityTo humans
The plant Allium caeruleum, commonly known as blue globe onion, is not considered toxic to humans. In fact, it's part of the Allium genus, which includes onions, garlic, and chives, many of which are edible. However, consuming large quantities of these plants, particularly for individuals who are sensitive, may lead to gastrointestinal irritation or discomfort. It is always prudent to consume plants that are known to be safe and to eat any plant material in moderation.
To pets
For pets, particularly cats and dogs, Allium caeruleum, known as blue globe onion, can be toxic. All members of the Allium family can be harmful to pets if ingested in significant quantities. The symptoms of Allium toxicity in pets can include gastrointestinal upset, such as vomiting and diarrhea, as well as more severe conditions like lethargy, abdominal pain, and even hemolytic anemia. Hemolytic anemia can be life-threatening and is characterized by symptoms such as pale gums, rapid breathing, and ataxia. Pet owners should prevent their animals from ingesting this plant and seek veterinary care if they suspect their pet has consumed any part of an Allium, including the blue globe onion.
CharacteristicsLife cycle
Perennials
Foliage type
Deciduous
Color of leaves
Green
Flower color
Blue
Height
1-2 feet (30-60 cm)
Spread
0.5-1 feet (15-30 cm)
Plant type
Bulb
Hardiness zones
4
Native area
Asia
Benefits
General Benefits- Ornamental Value: Allium caeruleum, commonly known as Blue Globe Onion, has striking blue spherical flowers that add a unique touch of color and visual interest to gardens and landscapes.
- Attracts Pollinators: The vibrant flowers of the Blue Globe Onion are known to attract bees, butterflies, and other beneficial pollinators, supporting biodiversity.
- Easy to Grow: It is a hardy plant that can thrive in a variety of soil conditions, making it a low-maintenance choice for both novice and experienced gardeners.
- Drought Resistant: Once established, Allium caeruleum is quite drought tolerant, making it suitable for xeriscaping and reducing the need for frequent watering.
- Deer and Rodent Resistant: The Blue Globe Onion is generally resistant to deer and rodents, which helps prevent the plants from being eaten and the need for pest control.
- Culinary Uses: While not the main focus of its benefits, the plant does belong to the onion family and may have edible parts commonly used in cooking.
- Companion Planting: Its strong scent can help deter certain pests, making it a good companion plant in vegetable gardens and ornamental beds.
Medical PropertiesThis plant is not used for medical purposes.
Air-purifying QualitiesThis plant is not specifically known for air purifying qualities.
Other Uses- Allium caeruleum, also known as Blue Globe Onion, can be used as a dye plant where its bulbs are processed to extract blue and green pigments for fabric coloring.
- In culinary arts, its colorful and showy flowers can be used to garnish salads and soups, adding a subtle onion-like flavor and a burst of color.
- The fibrous leaves of Blue Globe Onion can be twisted into threads or ropes in traditional handicrafts for small artisanal projects.
- This plant serves as an ornamental addition to bouquets and dried flower arrangements due to its striking blue spherical flowers.
- As a natural insect repellent, Blue Globe Onion can be planted in gardens to deter pests such as aphids and carrot flies from other crops.
- In the art of flower pressing, the Blue Globe Onion's flowers provide a unique shape and hue for crafting and botanical displays.
- Photography enthusiasts may use the Blue Globe Onion as a picturesque subject for macro photography due to its intricate blossoms.
- The plant can be used in educational settings for botany studies, particularly in discussions regarding bulbous plant species and their life cycles.
- The seed heads of Blue Globe Onion, when dried, can make interesting additions to potpourri mixes, contributing an earthy texture and visual appeal.
- Gardeners might utilize the structured growth pattern of Blue Globe Onion as a blueprint for creating formal garden designs or border edges.
Interesting Facts
Feng ShuiThe Blue Globe Onion is not used in Feng Shui practice.
Zodiac Sign CompitabilityThe Blue Globe Onion is not used in astrology practice.
Plant Symbolism- Unity: The spherical shape of Allium caeruleum's flower often symbolizes unity and togetherness, as it comprises many small flowers grouped into one larger, round bloom.
- Prosperity: The allium’s robust nature and its round, full bloom can symbolize prosperity and abundance, reflecting the fullness of wealth.
- Patience: These plants take time to grow and bloom, representing the virtue of patience in achieving one's goals.
- Humor: Their unusual appearance and height can be seen to bring a sense of whimsy and humor to gardens and arrangements.
- Good Fortune: In some cultures, the Allium caeruleum is believed to bring good luck, especially when planted in clusters.
- Strength and Courage: The plant's ability to grow in a variety of conditions symbolizes strength and the courage to thrive in different environments.
WaterBlue Globe Onion should be watered moderately once the top inch of soil feels dry to the touch. In general watering every 5 to 7 days will be adequate, depending on the climate and weather conditions. During the active growth period in spring and early summer, ensure consistent moisture by providing about one gallon of water per square yard each week. Once established, the plant is quite drought-tolerant and will require less frequent watering. Overwatering or waterlogged soil should be avoided, as this can cause bulb rot.
LightBlue Globe Onion prefers full sun conditions to thrive. The best spot for the plant is in an area where it can receive at least six hours of sunlight daily. This ensures robust growth and optimal flowering. While the plant can tolerate partial shade, the flowering may be reduced in less than ideal lighting conditions.
TemperatureBlue Globe Onion is hardy and can tolerate a range of temperatures but performs best when the temperature is between 55°F and 75°F. It can survive winter temperatures down to about -4°F, making it suitable for cooler climates. The plant should not be exposed to temperatures above 90°F for extended periods, as extreme heat can stress the plant.
PruningFor Blue Globe Onion, pruning typically involves deadheading, which means removing spent flower stems to encourage the plant to put its energy into bulb growth rather than seed production. Deadheading should be done after the blooms have faded but before seeds have formed. No regular pruning is necessary, and foliage should be left in place until it dies back naturally to provide nutrients for the bulb.
CleaningNot needed
SoilBlue globe onion thrives best in well-draining soil with a mix of sand, compost, and loam, favoring a pH of 6.0 to 8.0 for optimal growth.
RepottingBlue globe onion rarely needs repotting as it is typically grown as a perennial that can be left undisturbed for several years.
Humidity & MistingBlue globe onion is tolerant of a range of humidity levels and does not require specific humidity conditions to thrive.
Suitable locationsIndoor
Provide full sun and well-draining soil for indoor blue globe onion.
Outdoor
Plant in full sun with well-draining soil; water regularly.
Hardiness zone
4-8 USDA
Life cycleAllium caeruleum, commonly known as blue globe onion, begins its life cycle with seed germination, occurring in late winter or early spring when soil temperatures warm. The plant develops a root system and a basal rosette of leaves, from which a stem eventually emerges. As it enters the vegetative stage, leaves elongate and photosynthesis increases energy production for growth. Following the vegetative stage, the blue globe onion produces a distinct spherical cluster of blue flowers on a tall stalk in late spring to early summer, attracting various pollinators. Post-pollination, the flowers develop into seed capsules, and once mature, the seeds are released to the environment for dispersal. The plant then enters dormancy, with the foliage dying back to the bulb, which survives underground until the next growing season.
PropogationPropogation time
Spring-summer
Allium caeruleum, commonly known as blue globe onion, is typically propagated by dividing and replanting its bulbs. The best time to undertake this process is after the foliage has died back in late summer or early fall. To propagate by bulb division, dig up the clump of bulbs once the leaves have yellowed and carefully separate them, ensuring each division has at least one growth point. Replant the bulbs immediately, spacing them about 3 inches (7.6 cm) apart, at a depth of about 2 to 3 times the height of the bulb, in well-draining soil with plenty of sunlight. Water the newly planted bulbs to settle the soil around them, and they should begin to grow the following spring. This method of propagation is the easiest and most common way to cultivate more plants and maintain the health and vigor of blue globe onion.
