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.
How are allium leaves concealed?
When I saw several friends who were visiting staring carefully at some plantings in the far corner of my decorative garden, I knew I had struck gold in terms of landscaping. When I approached to join in on their chat, I noticed that they were focused on a group of deep purple irises that were surrounded by tall, silvery purple alliums. The composition’s different purple tones were nicely and harmoniously contrasted by the golden foliage of the neighboring shrubs. It wasn’t the irises or the shrubs, while both were extremely gorgeous in their own right, that attracted so many remarks from my friends. The alliums were the object of their attention!
Alliums, commonly referred to as attractive onions, weren’t always common in the landscape. However, gardeners are starting to take notice of them as they enjoy their beauty and see how they offer an architectural contrast to other decorative plants’ spreading or mounding forms. It’s exciting to notice these adorable bulbs popping out all over landscapes.
The broad botanical genus that comprises chives, shallots, leeks, onions, and garlic also contains ornamental onions. However, in contrast to their edible siblings, decorative cultivars are only developed for their eye-catching, spherical flower heads. The flower heads are composed of clusters of tiny, star-shaped flowers, and they are 1 to 10 inches wide. Some of the larger types’ flower heads may have 100 or more distinct flowers inside. The flowers might be white, yellow, blue, silvery lavender, or reddish purple, depending on the selection.
Most ornamental onion cultivars have flower heads that are elevated above a group of strap-like leaves. Early bloomers have unusually early spring foliage emergence, which typically dies back just as the plants begin to blossom. Alliums that bloom later in the season keep their lovely green foliage for a longer period of time. It is a good idea to place the early bloomers in the landscape so that the nearby vegetation will cover the wilting leaves.
Alliums draw bees and butterflies to the ornamental garden in addition to adding beauty and architectural interest. If you still need more encouragement to try alliums, there is some more good news. They are avoided by deer, rabbits, voles, squirrels, chipmunks, and other animals due to the leaf and bulbs’ slight onion flavor.
More than 300 species of the allium family are used as ornaments. The size of the bulbs varies greatly, usually in relation to the height of the plant as a whole. While some of the taller allium varieties reach a height of over 4 feet, several of the lower varieties only reach a height of 6 inches. The majority of cultivars reach a height of 18 inches or more and are suitable for the middle or back of the border.
The following are a few of the more well-liked allium species and hybrids that are planted in American gardens:
- Purple Sensation A. aflatunense Even though I enjoy many varieties of ornamental onions, this one is a personal favorite. In the middle of April, 2- to 3-foot-tall stems bear violet-purple flower heads that are 4 to 5 inches broad. The terrain is given depth and drama by the intense hue.
- Caeruleum, A.
- On 2-ft-tall stems, the modest 1- to 2-in. flower heads are a lovely shade of sky blue.
- A. christophii, often known as the Star of Persia, is an allium species with one of the largest flower heads. Hundreds of star-shaped florets are arranged in a loose, airy 10- to 12-in. broad pattern on a typical flower head.
- 1. The Giganteum
- This is one among the tallest representatives of the Allium genus, reaching a height of at least 4 feet. The persistent flower heads are typically 4 inches across.
- A. “Globemaster”On 3-foot-tall stalks, softball-sized flower heads of a silvery purple color bloom in May. Visitors to my garden were mesmerized by this variety.
- ‘Jeannine’ A. moly
- This smaller species blooms in the middle of the summer on 12-inch stalks and has beautiful yellow flowers.
- Schubertii A.
- This is undoubtedly one of the allium family’s more unusual members. The flower heads are colorful and extremely huge. It is described as a lavender fireworks display in other publications.
- Sphaerocephalon, A.
- Frequently called drumstick allium,
Around June, this later-blooming cultivar bears reddish-purple, egg-shaped flowers that are 1 to 2 inches diameter. Large clusters of this selection look the best when planted. In the summer, especially, it can withstand a little bit more dampness than its brothers.
- ‘Mount Everest’ A. stipitatum This variety, one of many white-blooming species, bears 6- to 8-inch snow-white blooms with dark green eyes on stems that to 3 feet tall.
- In a rock garden or at the front of a mixed border, plant the smaller, low-growing kinds. To add texture and height to the border, use medium-height variety. In mixed borders, the taller species and hybrids offer eye-catching vertical components. Although they can reach heights of 3 to 4 feet, unless the location is extremely windy, they don’t need to be staked.
- Use as a link between bulbs that bloom in the early spring and those that bloom in the summer.
- Plant them to draw hummingbirds, butterflies, and bees.
- Combine with vegetation to help disguise the dying back of the allium leaves. Some suggested mates include catmint, peonies, irises, and roses.
- From the lightest lavender to the deepest purples, combine with different hues. For instance, place the reddish-purple Salvia nemorosa ‘Caradonna’ selection beside the basic purple A. aflatunense ‘Purple Sensation’ selection. Plant “Giganteum” with a deep purple kind of iris like “Swingtown.” Plant burgundy drumstick allium close to the contrasting hues of golden Coreopsis for a more vivid color combo.
- For a traditional color scheme, combine the purple species with plants that have silver or gold foliage, such as Agastache foeniculum ‘Golden Jubilee’ or Artemisia or Stachys.
- For a refined and beautiful combination, use plants with variegated green and white foliage or white varieties with pale pink roses.
- To keep the spectacle continuing, space out the blooming times. For instance, ‘Purple Sensation’ blooms in May among the first, followed by A. giganteum. Early summer is when drumstick allium takes over, and late summer to early fall is when pink-blooming A. thunbergii ‘Ozawa’ blossoms. An indigenous variety called A. stellatum (American prairie onion) flowers from late summer to early fall.
- Keep the seed heads in situ after the flowers have faded to keep the garden interesting for the remainder of the summer.
- Use the dried flower heads for Christmas decorations or floral arrangements.
- To improve the show, let alliums to gradually colonize the area. While certain types invade more well than others, the species that are frequently sold are not regarded as invasive.
Although ornamental alliums are fairly simple to grow, they do have certain unique needs.
- Autumn is the best time to plant the bulbs. Alliums need a period of cold weather in order to bloom, much like the majority of spring-flowering bulbs need.
- The majority of alliums are native to sandy, arid soils, but they will thrive in clay if it has been improved with drainage. It’s crucial to have good drainage in the winter. The majority of alliums prefer dry soil and cannot withstand moist soil.
- LightAlliums can take some shade, but they thrive in direct sunlight. Make sure no other plants are casting any shade over their foliage.
- Plant DepthPlant alliums 3–4 times their bulb’s diameter deep. Bulb planting too shallowly may lead to poor flowering.
- Plant Distance
- Smaller allium species should be spaced 3 to 4 inches apart. Depending on the species, leave a gap of 8 to 12 inches between large species.
- The strap-like leaf may being damaged by frost as it develops in the spring. The bulb will still bloom despite it, but the plant’s look could be harmed by the damaged foliage. Late spring or early summer is when the foliage of species that bloom in the spring dies back.
Alliums can develop colonies or self-seed if they are content in a sunny, well-drained location. The growth of flowers may be hampered by crowding. The bad news is that. The good news is that you can now expand your allium collection for your garden or to give to friends. There are various ways to spread alliums:
- Division Allium bulbs frequently grow offsets. Lift overcrowded alliums out of the ground to divide them once the flowers have faded and the foliage has perished. Remove the offsets slowly from the “mummy bulb Replenish both of the “the offsets and the mother bulb.
- Aerial bulbils are produced in the flower head of a select few alliums, including A. roseum and A. sphaerocephalon. They can be painstakingly removed from the flower head and planted in compost that drains easily. Add a thin layer of compost over top of them, about 1/4 inch thick.
- Alliums can also be established from seeds, although the plants that result from this process take several years to attain flowering size. Plant seeds as soon as they are mature, or keep them in the refrigerator until spring and plant them when the soil reaches a temperature of at least 55 degrees. Within 12 weeks, the seeds should begin to grow. Keep in mind that hybrid seeds won’t produce fruit. A word of warning: Some species’ seeds might be harmful. Please do not give these to your pets or kids to eat.
Ordinarily trouble-free, ornamental onions are nevertheless susceptible to the same pests and illnesses as their culinary relatives. They might experience onion bugs, downy mildew, and onion white rot. Slugs, snails, and the allium leaf miner are among the pests.
The Definitive Horticultural Reference for the 21st Century: A-Z Encyclopedia of Garden Plants (The American Horticultural Society, rev. ed. 2004).
What are some uses for allium foliage?
The foliage of the allium often appears at least a month before the flowers do. Some species’ foliage starts to turn yellow and die off before the flowers are fully open. Plant the bulbs with other plants that will obscure the wilting foliage to help mask it. Alliums do well with hosta, astilbe, and perennial geranium.
When your alliums are blooming, you may anticipate seeing a lot of pollinators. Any type of habitat garden will benefit greatly from the inclusion of these bulbs.
Like their relatives in the vegetable garden, alliums hardly ever have insect or disease problems. Rarely do bothersome rats and deer show any interest.
Most alliums are perennial plants. They will typically bloom again if the species you are planting is winter hardy and the bulbs are suitable to the growing environment in your yard.
Caring for Alliums After They Flower
Allium wasted flower heads can be removed or left in situ once flowering is over. The seed heads are viewed as an intriguing decorative element by many gardeners. Depending on your environment, they may persist far into the beginning of the fall.
Large-headed alliums like Schubertii and Globemaster hardly ever produce viable seeds. Purple Sensation and drumstick alliums will reseed if the conditions are favorable. Simply remove the seed heads after the flowers have faded and before the seeds develop to prevent a carpet of tiny volunteers.
There are herbaceous alliums as well as alliums that grow from bulbs, including varieties like Millennium and Summer Beauty. These plants have a big root system and come back every year to blossom.
Alliums that emerge from bulbs require their foliage in order to generate energy for the blossoms of the next year. Therefore, it’s crucial to let these plants die back organically. The leaves may typically be removed with a simple tug once it has turned yellow and dried. Trim off the wasted blooms from herbaceous alliums with hedge shears or scissors once they have stopped blooming. This will maintain the plants’ clean appearance and might promote a second flush of blossoms.