Alliums can thrive in either full or partial shade, however full sun is preferred.
The bulbs are typically winter-hardy in hardiness zones 3–8. See this USDA Hardiness Zone Map to determine your growing zone.
Alliums require well-drained soil that does not become wet in order to be cultivated, just like the majority of other bulbs.
Where to Plant Alliums
Most alliums bloom in late spring, right after the last tulips and before irises and peonies, in perennial gardens. The flowers last for weeks and give the garden a balloon-like appearance as they float above it. After flowering, the foliage and flowers disappear, making space for summer perennials to take the lead. Allium christophii, Gladiator, Globemaster, Purple Sensation, and more excellent alliums for perennial gardens include these.
Alliums do well in rock gardens, where they flourish in the well-drained crevices between the boulders. Select species with smaller leaves, such as Allium sikkimense, Allium flavum, and Allium karataviense.
Alliums make great cut flowers, according to cutting gardens. The flowers remain a very long time and are easy to arrange thanks to their rigid stalks. You may guarantee that you’ll always have an abundant supply of flowers for bouquets by planting alliums in a cutting garden. You’ll receive flowers all season long if you select a variety. Purple Sensation, Allium atropurpureum, Mount Everest, Allium sphaerocephalon, and Allium tuberosum are all good choices.
Containers: Whether grown alone or in combination with other plants, many alliums thrive in containers. When the flowers blossom, you can relocate the planter to a visible location so that you can enjoy the flowers.
How to Plant Alliums
When to Plant: Bulbs-based alliums are planted in the fall, just after the first frost and before the ground freezes. Like other perennials, herbaceous alliums (such as Allium tuberosum and Allium millenium) have fibrous roots. You can plant these at any point of the growing season.
Planting Depth and Spacing: Planting depth is based on bulb size. Smaller bulbs, such drumstick alliums, should only be planted 3 deep in comparison to larger bulbs like Globemaster, which should be planted 5 to 6 deep. Follow the plant-specific directions on the packaging or on our website for the best results.
Planting advice: You don’t have to be concerned about deer, squirrels, or voles when growing alliums. Allium bulbs have an onion-like flavor that repulses them, and they almost invariably leave them alone.
How many sun hours do alliums require?
Select a planting place with well-drained soil and exposure to full to at least a half day’s worth of sun. Alliums are normally spaced 4 to 8 inches apart. They will require more space the larger the bulb. Since alliums don’t have a spreading growth habit, planting them close together makes them look nicer.
Are alliums sun-loving plants?
Light. While sweet alyssum enjoys the full sun, it does not appreciate extended dry spells. This plant will thrive in a spot with afternoon shade if your area is hot and dry.
What environments favor alliums?
Consider your garden space when choose which alliums to cultivate. Will you be bulk-planting in pots or growing in drifts through the border? as a component of a structured planting plan for prairies? Additionally, it’s crucial to consider the color of your alliums. Although most allium blossoms are purple, some are also blue, white, yellow, and pink in color. Also take into account the size of your allium—both the size of the flowers and the plant’s overall height. Allium flowers can range in size from a few centimeters to over 20 cm (8 in) in diameter, and their eights can also differ greatly.
Planting large, tall alliums singly or in drifts works nicely for varieties like “Purple Rain” and “Globemaster.” Allium christophii and other shorter variants grow well in containers. In prairie planting designs, drumstick alliums like Allium sphaerocephalon look fantastic.
Where to plant alliums
Alliums thrive in a sunny location with excellent soil drainage. They don’t care what kind of soil it is. Plant higher-growing cultivars in the back of a border and lower-growing varieties up front. Although alliums do well in containers, their strappy foliage can become ugly after flowering.
The leaves of alliums develop before the flowers do. As a result, they are frequently better suited to the center of a border where the faded foliage would be hidden and the flowers will put on a display. Plant alliums among attractive grasses and perennials to hide the fading foliage.
Grow alliums in broad drifts through the border or let them naturally grow in your lawn for a striking show.
How to plant alliums
Plant allium bulbs in the fall, at least four times their size deep (at least 15cm deep). It is preferable to plant them deeply rather than superficially.
There is no need to water them in if the soil is damp. Poor soils should be fertilized with a balanced fertilizer in the spring as growth begins to show.
Where in a garden should alliums be planted?
Alliums are a favorite among garden designers, and it is understandable why. With their striking shapes and glittering florets, these distinctive and incredibly appealing flower globes catch your attention. The seed heads remain interesting for months after the blooms have faded, and they bloom for weeks in late spring and early summer. Alliums are perennial plants that are consistently unaffected by deer or rats. Pollinators also adore them.
For ideas on how to design your own garden, consider how alliums and perennials are combined by garden designers. Continue reading to explore some instances of imaginative and surprising matching. (Note: Unlike herbaceous alliums like Allium ‘Millenium’ and Allium tuberosum, which are grown from fall-planted bulbs, this article focuses on perennial alliums.)
Combining Alliums with Other Perennials
Make your alliums dependent on each other. These flowers seem nicer when there are other plants growing beneath them because of their long, slender stems. The foliage of allium also disappears shortly after the flowering. You’ll be left with gaps if other plants aren’t there to fill them up.
Here’s another compelling argument in favor of planting your alliums in a bed of greenery. While the flowers are still in bloom, the leaves of some types, such as Purple Sensation and the majority of the big-headed species, start to turn yellow. The foliage of other perennials provides the finest cover for those leaves.
The perennial plants that go well with alliums are listed below. Many of them would be too tall later in the season. The perennials, however, are still young when the alliums bloom, so the scale still functions.
- Hosta
- Standing Sedum
- Decorative grasses
- Woman’s Mantle
- Nepeta (catmint)
- Salvia
- Lamb’s ears, or stachys
- Astilbe
- Lavender
- Geranium (cranesbill)
- Aquilegia (columbine)
- Dianthus (carnation)
- Santolina
- Peony
- Hemerocallis (daylily)
- Foxgloves
For more inspiration, consider the following alternative perennial and allium combinations:
Rock gardens benefit from Allium karataviense. Sedums like the golden “Angelina” have the ideal scale to work well as companions.
Nepeta and salvia nemerosa are underplanted with allium Mt. Everest in landscape architect Nick McCullough’s garden.
Plan for Contrasting Heights
While some alliums never grow taller than 6 inches, others can reach heights of almost 4 feet. This is why it’s critical to understand the types of alliums you’re planting and their intended locations.
The front of a flower bed is a good place to plant short ones like karataviense (6), ‘Graceful’ (10), christophii (18), and schubertii (15), as they are simple to admire. Place the tallest people in the back and the middle-sized people in the middle. Alternately, you may try a different strategy and utilize tall alliums like the sample “see through plants” below.
Get Creative and Experiment with Color and Form
In Staffordshire, England’s Trentham Gardens, I witnessed the arrangement that is depicted above. Large-headed alliums, possibly Gladiator, were coupled with waves of ornamental grass (Nassella tenuissima). It highlighted the individual features of these two quite different plants and was bold and unexpected in the best possible way. Do you have a spot in your garden that you could use this in?
Let the Seed Heads Linger
Be cautious when removing the wasted blooms from alliums once they have done flowering. Let the performance go on! The majority of species produce attractive seed heads that can last for several weeks or even months. This year, I didn’t remove the allium christophii until early September and brought the seed heads inside to enjoy around the home.
In the garden, allium seed heads look their best when planted in a location that is moderately open and not overly populated with other plants. This makes appreciating their distinctive shape simpler. Additionally, efficient air circulation keeps them dry, which makes them less likely to disintegrate.
Planning for Different Bloom Times
Each type of allium blooms at different times, as shown on our allium bloom time chart. This makes it simpler to prepare for certain plant combinations and to pace the bloom period such that alliums can bloom from May through early July.
A favorite springtime color combination includes peony leaves with burgundy tips and allium christophii.
When should allium bulbs be planted?
Most likely, when you think of alliums, you picture those plants with the traditional round, purple flowerheads on long stalks that make borders look amazing in late spring and early summer. Alliums, however, are much more than this.
There are alliums that are white, pink, blue, and yellow. There are some alliums that resemble a fireworks display, and others that resemble knotted dreadlocks.
You can identify that alliums are related to onions, garlic, and leeks by the aroma released when you crush the foliage. This family also includes chives (Allium schoenoprasum), which have delicious leaves that may be sliced and used to salads and dips.
Alliums are a favorite of butterflies and bees, and even the dried flowerheads look lovely in the border or in floral arrangements.
When to plant allium bulbs
The greatest time to plant alliums is in mid- to late-autumn, at the same time as tulips and daffodils that bloom in the spring. Allium bulbs are resilient and can withstand harsh winter weather if they are planted in soil that drains effectively.
Some attractive alliums, like “Allium sphaerocephalon,” flower in the late summer. Most ornamental alliums bloom in the late spring and early summer.
The majority of alliums thrive in full sun and well-drained soil. Tall alliums should be planted in a protected area to prevent the stems from blowing over in high winds. Plant purple-flowered chives (‘Allium schoenoprasum’), which appreciate afternoon shade, or yellow-flowered ‘Allium moly’ in shaded areas.
Tall alliums look great planted in broad swaths or punctuated across a border. Late-summer bloomer Allium sphaerocephalon has gorgeous wine-red flowers that stand out amid the grasses in prairie planting schemes.
Long, slender leaves on ornamental alliums fade back as the flowers emerge. To conceal the waning foliage, place allium bulbs under other low-growing plants.
Planting allium bulbs
- Remove any weeds by turning the dirt over. Dig in leaf mold or compost instead of using manure on heavy soil as this can change the soil’s pH level. Alliums thrive in soil with a pH that is neutral.
- Make a hole that is roughly four times the bulb’s depth.
- Put a bulb in the opening with the roots pointing down.
- Gently compact the earth after filling the hole.
Alliums can also be grown in large pots with soil that is a mixture of grit, John Innes No. 3 compost, and multipurpose compost.
Tips on caring for alliums
- Ground-planted alliums typically don’t require irrigation.
- In the spring, alliums grown in containers will require regular watering. However, avoid letting the compost become soggy as this could lead to the bulbs rotting.
- Crushed eggshells around plants, copper tape around pots, beer traps, or wildlife-friendly slug pellets can all be used to deter slugs and snails from eating new spring leaves.
- When the plants are in bloom, spread a general-purpose fertilizer to aid in the development of the bulbs, assuring healthy flowers the following year.
- Once the leaves have withered back, remove them.
- There is no need to deadhead the flowerheads unless you choose to because they still look excellent after flowering has completed. As long as they remain in place at the border, they may be ignored.
- Put pots in a greenhouse or up against a wall of a house in the winter to shield them from the cold weather.
Growing allium bulbs from offsets
Offsets, which are little bulbs affixed to the main bulb, are produced by many allium bulbs. These can either be planted directly in the ground or split from the main bulb and placed in tiny pots to grow on. Before they have developed enough to produce flowers, it will take a number of years.
Wait until the allium plants are through flowering before using a garden fork to carefully uproot the plants and inspect the bulbs for offsets. Replant the bulbs after removing any offsets.
Best allium bulbs to plant
Alliums come in a wide variety, from large to little, with flowerheads that are rounded or exotic-looking twisted. Here is a selection of the most well-liked alliums.
- One of the most well-known alliums, Allium ‘Purple Sensation’ has the traditional deep purple spherical flowerheads on long, robust stalks. 1 m (3.5 ft) high.
- Large circular purple flowerheads up to 15 cm (6 in) across on robust stems that are 80 cm (3 ft) tall characterize Allium ‘Globemaster’.
- As its name suggests, Allium giganteum is a true giant with dense, spherical purple flowerheads on stems up to 1.8 meters (6 feet) tall.
What ought I to grow in front of the alliums?
Alliums go well with heavy-foliage plants like peonies and iris; position them behind them. Excellent for bedding and mixed borders. Flower heads can be dried well. Many perennial plants, such as Echinacea (Coneflower), Phlox, Alchemilla mollis (Lady’s Mantle), Achillea (Yarrow), and Iris, complement alliums wonderfully.
Does dianthus prefer shade or the sun?
The genus Dianthus contains species that are both annual and perennial as well as biennial, in case you’re wondering whether dianthus are annual or perennial. Here are a few of the common names for the genus that you may have heard.
- Pinks come in enduring shapes. They are either fully or partially evergreen. The common name “pink” comes from the petals’ ruffled edges, which resembled pinking shears when they were cut.
- Short-lived perennial Sweet William is often grown as a biennial or annual.
- Dianthus caryophyllus carnations are a florist favorite because of their long stems and lengthy bloom period.
Height/Spread:
Height can range from 4 to 36 inches tall depending on the type. The width of the spreads varies depending on the variety and can be anywhere from 4 and 24 inches wide.
Color and characteristics:
Flowers have ruffled petals and can be solitary, semi-double, or double. With the exception of blue, they are available in almost all hues as well as patterned bicolors. The strappy, grass-like foliage comes in green, blue-green, and silver-green hues.
Toxicity:
Some people may experience brief skin irritation from dianthus foliage, with symptoms often disappearing after a few minutes. If pets consume the plants, they could become somewhat harmful.