
Light Needs

Mature Height

Mature Spread

Growing Zones
A time-honored addition to most informal gardens, Allium continues to be a gardener’s favorite. Large lavender umbels of flowers sway over fleshy green stalks with strap-like leaves at ground level. When you brush or squeeze any part of the plant, an onion fragrance will waft up to you, adding to their appeal in your garden. They make wonderful perennial additions to childrens’ gardens as well as wildlife gardens as bees and butterflies love them. Serendipity Ornamental Onion is a particularly prolific bloomer, sending up multiples of stalks with large flower heads rather than just one or two.
Native to temperate regions of the Northern Hemisphere, allium are hardy in Zones 4-8, growing in most of the United States except the very coldest winter regions and the very hottest summer regions. Gardeners the world over appreciate the allium family of plants, especially the ones with culinary benefits, onions and garlic, which have been used for thousands of years for food and for their medicinal benefits. Although technically all true alliums are edible, some are more suited for ornamental purposes, being either too strong, stringent or woody to be palatable. These are best enjoyed for their lovely flowers.
Serendipity Allium Care
Plant alliums in part to full sun, about 4 hours of sun is the minimum they prefer. Soil pH will be on the acidic side at 5.8 to 6.2. Use a sulphur based acidic fertilizer for best results. Alliums gain their classic onion smell from the sulphur in the soil. Water when first planted, then again during extended dry periods although alliums will tolerate some drought. Soil should be well draining to keep bulbs from rotting. Remove yellowed or damaged leaves. Deer and rabbit are not typically drawn to alliums so you shouldn’t have to worry about them browsing on them. Plant alliums outside about a week after the danger of the last frost has passed for best results.
Deadhead spent blooms to keep them from going to seed to extend the bloom season as much as possible. When the allium has ceased producing flowers, cut all spent flowers off but leave the foliage in place to garner energy from the sun. Once the foliage yellows, however, you may cut it down to the ground. Mulch with a good quality pine mulch to help soil retain its moisture and protect the roots in harsh winter regions. Although alliums produce seeds, these seeds may be viable as this is a hybridized variety. Divide clumps every three years to keep them from getting overcrowded.
Serendipity Allium Spacing
Space your alliums about 10 to 15 inches apart. These beauties will grow to about 20 inches tall and spread out to 15 inches wide. Alliums make an interesting addition to indoor flower arrangements. Plant them in masses in your landscape, in your informal cottage garden, and as an interesting thriller in your patio planters for height and that cool lavender color. You will find many ways to use alliums in your garden this spring.
Serendipity Allium Information
USDA Hardiness Zones: 4-8 |
Plant Type: Perennial |
Sunlight Exposure: Partial Sun to Full Sun |
Mature Height: 1 - 1.5 Feet |
Mature Width: 10 - 15 Inches |
Plant Spacing: 10 - 15 Inches |
Growth Habit: Upright |
Flower Color(s): Purple |
Flower Shade: Rosy Purple |
Seasonal Interest: Mid Summer Late Summer |
Foliage Type: Herbaceous |
Foliage Color(s): Blue-Green |
Attracts: Bees, Butterflies |
Resists: Deer, Rabbits |
Tolerates: Drought |
Features: Attracts Pollinators, Cut Flowers, Deadheading Not Necessary, Fragrant, Low Maintenance, Award Winner |
Uses: Border Plant Container Cut Flower Mass Planting |
Plant Brand: Proven Winners |
Botanical/Scientific Name: Allium hybrid USPPAF, Can PBRAF |
- SKU:
- ALLSE
Container Sizes
Please Note: The pictures below are to give a general representation of the different container sizes. The actual size/ages of plants are estimates and will vary based on type of plant, time of year, last pruning & many other factors.

Quart Pot
Also Known As:
Quart
Plant Age:
~ 6 months - 1 year
Plant Size:
~ 4"-8"
Pot Size:
~ 4.75"H x 4.5"W
Volume:
1.50 quarts

2.5 Quart
Also Known As:
2.5 Quart Pot
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 8"-12"
Pot Size:
~ 6.5"H x 6.5"W
Volume:
2.20-2.30 quarts

#1 Pot
Also Known As:
#1 Container
1 Gallon
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 10"-14"
Pot Size:
~ 7"H x 7.75"W
Volume:
2.26-3.73 quarts

#2 Pot
Also Known As:
#2 Container
2 Gallon
Plant Age:
~ 1.5 - 3 years old
Plant Size:
~ 12"-18"
Pot Size:
~ 9.5"H x 9.5"W
Volume:
1.19-1.76 gallons

#3 Pot
Also Known As:
#3 Container
3 Gallon
Plant Age:
~ 2 - 4 years old
Plant Size:
~ 12"-30"
Pot Size:
~9.5"H x 11"W
Volume:
2.32-2.76 gallons

#5 Pot
Also Known As:
#5 Container
5 Gallon
Plant Age:
~3-4 years old
Plant Size:
~ 20" - 60"
Pot Size:
~11" H x 10 1/2” W
Volume:
3.5 - 4 gallons

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Arrival Guarantee
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Pre-Ordered Plants
Pre-ordered plants are scheduled to ship in Spring 2025. We carefully plan our shipping dates based on your USDA Plant Hardiness Zone to ensure optimal planting conditions upon arrival. Want it sooner/later? Reach out, and we'll try our best to accommodate.
Estimated Spring Shipping Schedule
Estimated ship week for pre-ordered plants will ship based on growing zones as shown below.
Growing Zone | Estimated Ship Week |
---|---|
Zone 10 | March 24th |
Zone 9 | March 31st |
Zone 8 | April 7th |
Zone 7 | April 14th |
Zone 6b | April 21st |
Zone 6a | April 28th |
Zone 5b | May 5th |
Zone 5a | May 12th |
Zone 4 | May 19th |
Zone 3 | May 26th |
Note: These are only estimated ship dates. Plants may ship out later depending on weather & growing conditions of the plant.
Note: Only plants indicated as pre-order will ship as shown above. All other plants and hard goods will ship as normal.
Plants Shipping Now
Plants that are currently in stock typically ship within 2-7 business days after your order is placed.