Allium ‘Purple Sensation’ is one of the most popular ornamental onions grown by gardeners. This striking allium is prized for its vibrant spherical blooms in rich shades of purple. But when exactly does this beauty burst into bloom each year? Understanding the factors that influence the bloom time of ‘Purple Sensation’ allium helps gardeners plan out their flower beds and borders for non-stop color.
Allium ‘Purple Sensation’ is a hybrid ornamental onion developed by Dutch breeders in the 1950s. Like many ornamental alliums, it forms a clump of slender, upright foliage that remains attractive even when not in bloom. The leaves are grass-like and grayish green in color.
In late spring, typically May or June, sturdy flower stalks emerge from the leaves, eventually reaching 18-30 inches tall. At the tips of the stems, eye-catching, rounded flower heads measuring 4-5 inches across form. Composed of dozens of tiny star-shaped purple florets, the blooms start out deep purple and lighten slightly to lilac-purple as they mature.
This plant is great for adding to flower beds, borders, containers, and cut flower arrangements because it attracts pollinators like bees and butterflies. Even after the flowers are gone, the spent blooms can be left in the garden to look nice.
What Factors Influence Bloom Time?
Many variables influence when ‘Purple Sensation’ allium comes into flower each year. Factors like climate weather patterns planting time, sunlight exposure, and soil conditions all play a role in determining bloom time.
Climate and Location
Climate is one of the biggest factors that impacts bloom time. In cooler regions with shorter growing seasons, ‘Purple Sensation’ will bloom later than in warmer climates. Gardeners in USDA plant hardiness zones 4-5 can expect blooms in June. From zones 6-9, flowers typically appear in May.
Within the same hardiness zone bloom time may vary by several weeks depending on the precise location. Local microclimates also come into play. Areas that warm up earlier in spring will see earlier bloom times compared to cooler pockets.
Weather Patterns
Unseasonably cool or warm spring weather can shift bloom time earlier or later. Heavy rain, drought, frost, and other unusual weather events may also delay or accelerate flowering. Following an extremely cold winter, bloom may be postponed as the bulbs recover.
Planting Time
When ‘Purple Sensation’ bulbs are planted affects their subsequent bloom time. Fall planted bulbs often flower earlier than those planted in early spring. However, spring planted bulbs can sometimes bloom the first year while fall bulbs may take a year or two to reach maturity.
Sun Exposure
Full sun to part shade areas tend to have earlier, more numerous blooms than heavily shaded areas, where flower growth is slower.
Soil Conditions
Rich, well-draining soil keeps bulbs healthy and fuels rapid spring growth and flowering. Poor, heavy, soggy, or nutrient deficient soil can delay bloom time.
Typical Bloom Periods
While bloom time varies, the average for Allium ‘Purple Sensation’ falls within these ranges:
- USDA zones 4-5: Late May to mid June
- USDA zones 6-7: Mid May to early June
- USDA zones 8-9: Early to mid May
But blooming can happen up to three to four weeks earlier or later, depending on things like soil, climate, and spring weather patterns in the area. Every year, gardeners should keep an eye on the plants and the site to find out when the best time is for them to bloom in their area.
Extending the Bloom Period
Even though each “Purple Sensation” flower head only lasts one to two weeks, there are ways to make the whole bloom last longer:
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Plant bulbs at different times in fall, winter, and early spring to stagger flowering.
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Site some bulbs in warmer microclimates, and others in cooler spots to spread out bloom.
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Deadhead spent blooms to encourage potential re-bloom and prevent self-seeding.
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Stake tall flower stems to prevent flopping, which shortens bloom time.
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Provide consistent water during bud development and flowering.
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Apply an all-purpose fertilizer when growth begins in spring.
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Divide congested bulbs every 2-3 years to maintain plant vigor and blooms.
Planning a Garden with Allium ‘Purple Sensation’
When designing flower beds and borders, keep bloom time in mind. Combine ‘Purple Sensation’ allium with other spring-flowering bulbs like tulips, daffodils, and hyacinths for an extra long season of color. For summer interest after the spring bulbs fade, interplant with perennials like coral bells, catmint, yarrow, and Russian sage.
Observe the performance of ‘Purple Sensation’ in your unique garden conditions and make note of its ideal bloom time. Use this information to plan striking combinations of flowers and foliage that provide a continuous parade of color from spring through fall. With its vibrant spherical blooms and adaptability, ‘Purple Sensation’ allium is an exceptional addition to gardens in many climates.
Mature Plants (2-4 years old)
| Container Size | Actual Volume | Metric Equivalent |
|---|---|---|
| #2 Container | 1.19 – 1.76 dry gallons | 5.24 – 7.75 dry liters |
| #3 Container | 2.15 – 2.76 dry gallons | 8.14 – 12.16 dry liters |
Young Plants (6 months to 18 months old)
| Container Size | Actual Volume | Metric Equivalent |
|---|---|---|
| 2″ x 2″ x 3″ | 0.18 – 0.21 dry quarts | 0.20 – 0.23 dry liters |
| 4″ Container | 0.31 – 0.87 dry quarts | 0.35 – 0.96 dry liters |
| 4.5″ Container | 0.65 dry quarts | 0.72 dry liters |
| 6″ Container | 1.4 dry quarts | 1.59 dry liters |
| 1 Quart | 1 dry quart | 1.1 dry liters |
| 5.5″ Container | 1.89 dry quarts | 2.08 dry liters |
An Amazing Summer Bloomer! ‘Serendipity’ Allium
FAQ
How long do Purple Sensation alliums bloom?
Blooming in late spring to early summer, this spectacular Allium enjoys long-lasting blooms and makes outstanding cut flowers that will last for 2 weeks. This beautiful plant grows to be 28 to 36 inches (70 to 90 cm) tall, and it comes back every year.
What not to plant next to alliums?
Also, alliums need a lot of sun, so plants that like deep shade, like ferns, hostas, and epimediums, are not good companions. Sep 14, 2023.
Do alliums bloom all summer?
While most allium varieties bloom in late spring to early summer, some alliums, particularly the clump-forming types, can extend their bloom time into mid to late summer, and even early fall in some cases.
What is the longest flowering Allium?
The Globemaster is undoubtedly the longest-blooming allium, with a blooming period of six to eight weeks. During these weeks, fresh flowers continually appear.