Alliums are those gorgeous flowering perennials in the spring garden with the big, round purple flower heads on tall, green stems. Planted from bulbs in fall, they are easy to grow, attract bees and butterflies, and (bonus) deer and rabbits don’t like them.
This is part of my Best Flowering Plants for a Cottage-Style Garden series.
I love alliums in spring and so do the bees! Just as the early spring tulips and daffodils are finishing up, it’s allium time.
There’s nothing quite like these tall, bold flowering plants with their giant purple flower heads.
As winter fades out, there are few food sources available, and the bees go wild for them, marking the transition to the warm growing season.
Alliums are bulb plants. Planted in fall, they will flower in spring, and provide blooms for several years to come.
The bulbs will gradually multiply, and the original bulbs will gradually weaken or die off.
At some point you may need to divide the bulbs to give the babies adequate growing space.
Allium flowers also produce seeds, which may sprout in the garden as well.
I’ve certainly found that alliums spread around my garden (which I love), but I’m not entirely sure if it was by seed or bulb, or, more specifically, from squirrels digging them up and moving them.
Allium Facts & Growing Tips
How to Plant Ornamental Allium Bulbs
The best time to plant allium bulbs is in fall after your first frost but before the ground is frozen.
Follow the directions on your bulb pack or plant at a depth 3x the size of the bulb. If the bulb is 2-inches tall, plant it 6-inches deep.
Light Exposure Definitions
Choose a location with sun or part-sun in spring.
As with any bulbs, ornamental alliums need well-draining soil because they rot if waterlogged.
Alliums bloom in spring. Allow foliage to die off after blooming—this is when the plant replenishes its energy for the next blooming cycle.
You can divide the bulbs any time the ground is workable. It’s recommended to do so before or after flowering so you don’t disrupt the flower cycle.
How to Sow Ornamental Allium Seeds
Allium seeds are slow growing—that’s why it’s more common to grow from established bulbs. It can take years from seed to flower.
If your seeds come from a cultivar in your garden, they may not grow flowers true to type but it’s always fun to see what you get.
Some species need cold stratification to germinate. This would occur naturally in a cold climate garden.
In your home, you can use the method shown here for delphinium seeds.
If you don’t know if they need stratification, try a germination test first to see if the seeds will sprout without this process.
Alliums naturally disperse their seeds in fall, winter, and spring. Seed packets recommend sowing after last frost in spring. Be sure to mark the location with long-lasting plant tags since growth will take several years.
Allium Plant Facts
Common Name: Allium, Ornamental Allium
USDA Hardiness Zones: 3 to 8
Cultivars: Between 200-900, depending on how it they are categorized; the taxonomy of allium is poorly understood
Origin: Northern hemisphere, Asia, Africa, South and Central America
Type: Herbaceous geophyte perennial with true bulbs
Height: 5-150 cm (up to 60 inches: 5 feet tall)
Light: Full sun to partial shade
Soil: Well-drained soil
Flower Times: Late spring to early summer
Colors: Light to dark purple, some are reddish-purple
Fertilizer: Depends on your soil—get a soil test to learn any nutritional needs
Attracts: Bees and butterflies
Avoided by: Deer and rabbits
Propagation: Plant bulbs in fall after first frost but before ground freezes
Planting depth: 3x the height of bulb
After blooming: Allow foliage to die off naturally as it provides fuel for next year’s growth. Seed heads (old, dry flowers) look lovely in winter garden.
Divide bulbs: Before or after flowering.
Toxicity: None known. Ornamental alliums are related to edible onions. Research first.
Trivia: The word allium is Latin for garlic. Allium sativum means ‘cultivated garlic‘. Some alliums are edible; some are strictly ornamental. The pungency of edible alliums is determined by the sulfate content of the soil: the more there is, the stronger the flavor.
Find Your Frost Dates & Hardiness Zone
- Plant Hardiness Zones | United States | Canada
These are listed on seed packets and plant tags to guide your choices.
DIY Garden Art Alliums
This craft project is made from recycled items including old nails and a softball. Follow the tutorial to make decorative alliums for your garden.
~Melissa the Empress of Dirt ♛
A Weekly Indoor & Outdoor Seed Sowing Plan for Beginners
by Melissa J. Will
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