Allium

ALLIUM

THERE IS NOTHING QUITE LIKE A ‘GLOBEMASTER’, CHRISTOPHII, OR GIGANTEUM ALLIUM IN BLOOM. THEY ARE TALL AND IMPOSING, BURSTING WITH HUGE BALLS OF PURPLE. THEY PEAK DURING THE TIME IN THE GARDEN WHEN TULIPS HAVE FADED AND THE BIG SHOWY PERENNIALS HAVE NOT YET COME INTO BLOOM.

The plants are not liked by deer and rabbits, take up very little room at ground level, and can be packed into tight spaces. Most important, planted among catmint, poppies, and comfrey, as in my long pergola garden, the varying shades and heights and textures of the allium create a veritable showstopping event.

Nonetheless, alliums pose a challenge for the home gardener. They bloom once a year on stiff upright stems and, unless planted in larger numbers, can look out of place in a border. If they emerge before the last frost, their leaves might turn brown and look in poor health during the blooming period. They do not multiply like daffodils and countless other small bulbs. They may last just one season. And because they are, actually, onions, they can smell like onions when blooming.

I started planting allium, all different types, in my Turkey Hill garden. I loved the accents of purple and mauve and violet, gently protruding over the other plants. I especially favor the very large round blooming types that are made up of hundreds of purplish florets on tall stems, including ‘Ambassador’, ‘Firmament’, A. giganteum, ‘Globemaster’, and ‘Mars’.

My favorite of all is what I have nicknamed “fireworks”—A. schubertii, producing on each stem a volleyball-sized bloom with rosy, purple star-shaped florets. I plant these incredible bulbs at the front of the pergola in Katonah and in the long borders and beneath hostas in the terrace beds at Skylands. In Maine, they bloom right around the Fourth of July and they are indeed a cause for celebration.

If you are adventurous, there are other types you should try in your garden: A. stipitatum ‘White Giant’, similar to A. giganteum and ‘Mount Everest’; A. unifolium, a shorter version with half-dollar-sized umbels in pink, lavender, or white; A. karataviense, which has broad glaucous leaves and comes in bright pink-red or lilac; and A. bulgaricum, with pendant greenish-white flowers tinged with purple.

For the vegetable gardener, try A. senescens, an ornamental onion; A. altaicum, another ornamental onion, which is architectural in form and very pretty in an arid garden; and, of course, A. tuberosum, or garlic chives, which have not only lovely white flowers but also delicious leaves that can be tied into knots, and steamed or sautéed in the Chinese style. The latter are truly perennial and last in the garden for many years.

There is one story I tell everyone when the subject of alliums comes up, the gist of which is “never, ever, tell children to ‘just look, don’t touch’ when it comes to alliums.” The attraction is just too great, and the ball-shaped flowers snap off easily, and can be played with for hours. It’s much better to tell them, “No! No! No!” Forbid them to even go near them! If not, every flower will be pulled off, played with, and your garden will be sad without its beautiful umbels of purple and blue and pink and white. Trust me! I’ve seen it happen many times. And who can blame the children? These beautiful, exuberant puffballs are nothing short of irresistible.

Alliums, or ornamental onions, are one of nature’s eccentric beauties. They can stand on their own as the stars of an arrangement. This tall, dark, and slender contemporary studio-ceramic vase gives white ‘Mount Everest’, which can climb up to 4 feet tall, even more dramatic presence. Kevin staggered the heights of the stems to give this arrangement a freeform look and to keep the blooms from canceling each other out. Foliage (these are Rodgersia aesculifolia leaves) softens the bouquet and draws the eye to areas that would otherwise be left bare.

Alliums’ sturdy stems make them particularly suited to upright arrangements. To create a looser-looking ensemble, Kevin crossed the stems to make a framework for a gathering of rose-purple A. schubertii (at left) and ‘Purple Sensation’ and white Allium nigrum (at right) in vintage blown-glass leech bowls. (I have a collection of these curious vessels, which doctors once used to store the worms used in the practice of bloodletting.) Allium flowers fade beautifully from one shade to another throughout their bloom cycle.

GROWING & ARRANGING

ALLIUMS ARE POPULAR, AND WITH GOOD REASON: THE UNUSUAL, SPHERICAL, STARRY FLOWERS ON LONG, 
SKINNY STEMS CAN ADD STRIKING BURSTS OF COLOR AND TEXTURE TO ANY GARDEN OR ARRANGEMENT.

Alliums create fireworks wherever they turn up. I grow many varieties, and like to combine several in a single bouquet. Kevin gathered ‘Mount Everest’, ‘Globemaster’, ‘Gladiator’, and other alliums at the potting shed at Turkey Hill. He arranged them in a vintage European glazed bread bowl as well as in American galvanized tin pails. The groups show off the alliums’ range in size, shape, and color—the deep purples, lavenders, silver, and white all work together. It’s as if he captured shooting stars in motion. One of my favorite varieties is the spiky, sunburst-shaped A. schubertii, displayed all by itself in the low tin bucket.

HOW TO GROW

Spring- and summer-blooming alliums have many attractive features, including that they’re adored by pollinators like bees and butterflies, yet resistant to rabbits, rodents, and deer.

ZONE Alliums come from the United States, Central Asia, the Middle East, and China, among other places. Very few exist in the Southern Hemisphere, however, so although some species and cultivars do well when grown from Zones 3 to 9, on the whole they do not perform well south of Zone 8. Check each species’ growing details carefully.

SOIL To get alliums to thrive, you need to plant them in soil that is loaded with compost and other organic matter, and make sure that it is well drained to avoid bulb rot. From early spring until the alliums have finished blooming, feed them with a slow-release bulb-specific fertilizer containing bone meal, potassium, and superphosphate, such as Holland Bulb Booster (9:9:6).

LIGHT Grow these showy bulbs in a garden that gets full sun, even in the height of summer, when surrounding trees are leafed out. You may have luck with some shade, however; I’ve lined the length of my pergola in Katonah with alliums and planted others in the flower garden and around the houses; some have grown nicely in partial shade.

CHOOSING Bulbs vary in size but all should be firm. Ensure that the bulbs are fresh and keep them dry until planting, as they are very prone to black mildew.

PLANTING The time to plant allium bulbs is in autumn, before the ground has frozen. Plant them at a depth of about three times the diameter of the bulb, with the somewhat flattened root end facing downward. Spacing depends on the species (from the large A. giganteum at 12 inches apart to the more petite A. caeruleum at 2 inches apart). Alliums (especially the smaller-flowered varieties) can return year after year under the right conditions. The larger-flowered varieties tend to die out after three to four years, however, so you’ll need to replace them with new bulbs.

WATERING While the plants are growing, give them at least half an inch of water every week from early spring through the end of bloom. The dormant plants like dry soil, so don’t water them after they’ve finished blooming. However, if other, thirstier plants share the same bed, be sure to give them the water they need—they’ll soak up the moisture before it compromises the alliums.

PRUNING Don’t remove the leaves, no matter how unsightly, until they have completely browned. They’re needed to supply energy to the bulbs. You can remove the spent flowers before they go to seed, then save the seeds and propagate from them, or divide the bulbs. I love the look of the dry flowers in the fall, so we’ll often leave them in the garden until they begin to deteriorate.

TROUBLESHOOTING One of the few downsides to growing alliums is that, like many bulbous plants, they have leaves that can turn scraggly when their flowers bloom—one reason why many gardeners interplant alliums with perennials. The latter cover the limp foliage at alliums’ bases without obstructing the blooms up top. We use peonies, baptisia, catnip, and lilies.

By cutting the stem very short, you can turn one allium into a centerpiece by placing it in a small vessel or by grouping individual spheres. Here, Kevin used A. albopilosum, ‘Firmament’, ‘Purple Sensation’, and a dried blossom in pressed-glass sugar bowls in the sawtooth pattern.

HOW TO ARRANGE

CUTTING Harvest alliums when they are just fully bloomed. It’s important to cut them in the early morning, using a sharp knife. Ornamental alliums can give off an onion scent, especially when the stems are crushed. Cutting cleanly helps to minimize the aroma. Immediately put them in fresh water, and change it regularly. Most alliums should last about two weeks.

ARRANGING Arrangements can be minimal and modern or lush and romantic, but they are always captivating, thanks to the plants’ otherworldly blossoms. You can leave the stems long or cut them short—allium is equally declarative as a bloom in a shallow vessel as with stems standing tall. If you’re arranging a mass of alliums, use a trumpet-shaped vase to prevent the blossoms from sticking together (larger-flowered varieties are especially prone to this). Trim the stems to slightly different lengths for a staggered effect. Some small species can resemble tassels or pom-poms and are great for softening a mixed arrangement. The larger globes can look dramatic all alone.

There is so much movement in the bloom of an allium, especially in A. schubertii, at far right, which resembles a starburst. 
It seems fitting, then, to arrange the sparklers singly (including A. albopilosum) in gleaming English brass candleholders set on a decorative tole tray.