Ornamental Alliums: Unique Flowers for the Perennial Border
Alliums are one of the largest genera in the plant world, with more than 750 known species. The lowly onion and its close relatives, garlic, leeks, chives, and shallots are the most familiar to most of us.
This huge group of plants also includes many attractive and striking perennials for the flower garden. If you grow chives in your herb garden, you will have a good idea of the ornamental potential here.
Gardeners have become fascinated with the larger alliums, particularly the giants. We have a whole group of beautiful new flowering alliums for the perennial gardens. Most bloom in late spring, so they bridge the gap nicely between the tulip and daffodil season and early summer blooming peonies and poppies.
More About Alliums
Alliums are herbaceous perennials, meaning the foliage dies down to the ground annually. In some cases, this happens before flowering; in others, the foliage remains until the first frost.
Some have broad flat leaf blades, while others have tubular leaf blades formed like a drinking straw. The leaves sprout in spring from a bulb, which can be a single bulb or a cluster.
Allium flowers are mainly held erect on the tip of a stem or scape, and form a pom-pom-shaped flowerhead. Others have star-like clusters of flowers, and a few have hanging pendants of blooms. Each plant will flower only once in a season and the seed heads, if left on the plant, can add textural interest in the fall.
How to Grow Alliums
Alliums can be started from seed easily in spring and transplanted into the ground when about 6 inches tall. As they grow, an underground bulb will form; and each year, new foliage and flowers will rise from this bulb. Many alliums produce little bulblets or offsets around the parent one, and these can be removed and planted. This is the most common method of allium propagation. Other alliums will form bulblets, known as bulbils, from the flowerhead.
Many nurseries and seed companies sell allium bulbs for fall planting. When planting the bulbs, choose a sunny and well-drained spot, as the bulbs will rot in constantly damp soil. They require five to six hours of sun.
Dig a hole for each bulb, place it top up, and cover with soil. Alternatively you can dig a larger hole and place several bulbs on the bottom before covering them with soil. Spacing depends on the type of bulb and the expected size of the grown plant. Since many have a single blossom atop a tall stem, they will look more attractive planted in a group.
Gorgeous Alliums for Your Garden
Ornamental alliums come in a range of heights and colors, suitable for a sunny and not-too-moist spot in the garden or in perennial borders. Easy to grow, these beauties are deer and rabbit resistant. They are also magnets for butterflies. The following are some of the most commonly grown varieties.
Blue Globe (Allium Caeruleum)
Allium caeruleum is known as the blue globe. It sports a good-sized, dense ball of deep blue flowers rising up to 60 centimeters above its strappy leaves. Give it full sun and average to dry well-drained soil, and plant drifts of this beauty for a stunning blast of lavender blue colour.
Nodding Onion (Allium Cernuum)
The charming and delicate 'nodding onion', with umbels of mauve to lilac flowers, is a good rock garden addition. It shows well at the front of a border, as it grows just 12 inches tall. Once the flowers have bloomed, the nodding onion dies down until cool weather, when new leaves will emerge.
This North American wildflower attracts hummingbirds and butterflies.
Chives (Allium Schoenoprasum)
Allium schoenoprasum is a select form of chives, with extra large rosy-purple balls of flowers. Use this as a border or a herb garden plant, as the foliage can be used like common chives.
This blooming onion has unique twisting leaves of a blue-green or blue-grey color rising spirally from the base. It has small clusters of pink to lilac flowers rising from the leaves in late summer. Allium senescens is suitable for borders, rock gardens, or as edging, as it grows in dense clumps about 10 inches high. Uniquely, it has true bulbs rising from a rhizome, making it easy to divide.
This sensational variety, Allium hollandicum, has rounded heads full of deep violet flowers. Growing to 40 inches in height, it is a perfect addition to a sunny perennial border, and makes a good cut flower as well. The short leaves die down by the time the flowers bloom, so it is best surrounded by greenery.
With very dramatic flower clusters that grow to 4 to 8 inches in diameter, Giganteum is one of the more common ornamental alliums. The balls of lavender-purple blooms rise up to 48 inches above ground, making a bold statement. The cut flowers are striking in floral arrangements.
Plant them at the back of a border, as the leaves are not attractive. This giant allium is maintenance free, hardy, and multiplies if left undisturbed.
This hardy and less common allium has one of the most unique and striking blossom heads. Allium schubertii looks like an exploding sparkler, with up to 200 individual florets thrusting outwards, so the whole airy ball can reach 15 inches in diameter!
The long-lasting flowers can be pink or purple and are replaced by fluffy seedpods. It is a real conversation piece in the garden or as a cut flower.
Sicilian Honey Garlic (Allium Nectaroscordum)
Another deciduous perennial related to allium is the Nectaroscordum or Sicilian honey garlic—their bruised leaves exude a garlicky smell. This species has large drooping heads of white or cream flowers, tinted pink, purple, and green. The flowers, which bloom in early summer, are followed by erect seed pods that are quite decorative.
Growing up to 4 feet tall, the Sicilian honey garlic is a stunning plant for perennial flower beds. This plant is native to southern France, Italy, and Sicily, so it does best in Mediterranean type climates.
Graceful Beauty (Allium Amplectum)
The Allium amplectum is known as the ‘Graceful Beauty’. It has fine-textured grass like foliage. Its bright-white flowers are speckled in purple, forming a dainty flower sphere 2 to 3 inches across. The fragrant flowers attract bees and butterflies. Once the flowers are finished, the plant goes completely dormant.
Like most alliums, this is deer, squirrel, and rabbit resistant. It is also toxic to dogs and cats.
A Unique Addition of Shape, Size, and Color
We have just touched on the ornamental alliums, and as you can see, they can make a unique addition of shape, size, and color to borders, rock gardens, and cut bouquets.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
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© 2020 Nicolette Goff