May 20, 2008 4 min read

Onions are a great plant for flower gardens. That’s right, I said onions.

Not the kind one can grow in the vegetable garden, though I grow those, too. And I’m not talking about the “Bloomin’ Onion” you can order at Outback Steakhouse.

I’m talking about ornamental onions.

Ornamental onions are in the genus Allium. There are some 700 or so species of these flowering perennials-some bulbous, others are rhizomatous. A lot of the ornamental onions I’m familiar with bloom in late spring and early summer, though I have read that some bloom in the fall.

The ornamental onions are, of course, related to edible onions, A. cepa, and garlic, A. salivum.

They are all in the lily family.

Like their relatives, the leaves of ornamental onions will express a pungent odor you’d recognize as distinctly onion if you crush them.

Perhaps it’s this odor that puts ornamental onions in the “deer-resistant” category.

The flowers of ornamental onions – actually, clusters of individual flowers, as a group called umbels – range from marble-size to the size of a volleyball.

Height of the flower stalks also varies, depending on species, from six inches to four-plus-feet tall.

Flower color is frequently in the purple spectrum and also pink and white, but there are a few with yellow flowers.

Alliums fit in as well in heirloom gardens as they do in contemporary gardens.

Some naturalize readily. Others make good cut flowers. And yet others dry well.

In fact, I saw photos several years ago of a garden where the clever gardener spray- painted the tall, dried flower heads of a variety of large allium to fool passersby.

What fun she had!

What ornamental onions require is simply a sunny location, with well-drained soil. Something to keep in mind is that the foliage of most ornamental onions is not ornamental (an exception, A. karataviense has broad decorative leaves), so it is a good idea to plant them with companion plants that will hide the leaves.

It also is a good idea to plant several allium – one will look lost, while several will add visual punch to a garden.

There are dozens and dozens of ornamental onions to choose from, including A. cernuum, a North American native also called nodding onion, that is small in stature, but vigorous and very adaptable.

The allium with the most impact would be the hybrid “Globemaster.” This ornamental onion’s three-foot-tall flowers can be softball-to-volleyball size. Pinkish-purple in color, there are hundreds of individual blooms on each umbel, and they produce secondary florets that extend the show.

An incredible hybrid, it also has a high price tag. A single bulb can cost nearly $10, but often the per-bulb price decreases with quantity purchases.

A. giganteum has flower stalks four feet tall or more.This species from Asia has softball-size round umbels that are lilac-colored and densely arranged.

Allium “Gladiator” also has softball-size umbels, but flower stalks only reach two or three feet tall, with flower color leaning more towards purple.

A. sphaerocephalon, called “drumstick allium,” has maroon-to-dark-purple, quarter-size flowers atop 18-to-30-inch stalks. This species easily reseeds and often forms small colonies.

A. moly has fabulous, bright yellow flowers. Its golf ball-size umbels have up to 30 star-shaped flowers on stems up to about a foot tall.

Better for the front of the border because of its size, A. moly increases rapidly and is good for naturalizing.

Another ornamental onion that is particularly interesting is A. schubertii, a plant that has very large, spidery-looking umbels on one-to-two-foot stalks.

One of my favorite alliums is “Hair.” Its flower head is a cluster of aerial bulbils with leaves sprouting out at every angle.

Talk about having a bad- hair day!

This ornamental onion garners lots of looks and laughs.

Plant the bulbs of ornamental onions in the fall.

They are available from several mail-order sources, including Brent and Becky’s Bulbs, John Scheepers Inc., and McClure & Zimmerman. These companies also have Web sites.

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Susan Brimo-Cox gardens, observes nature and writes in Ohiopyle.

Readers can send questions or comments to her at naturesgarden@brimo-cox.com.