Schubert's Allium Plant Profile

Spring Bulb That Is Dramatic but Toxic

Seed head of Allium schubertii.
David Beaulieu

Schubert's Allium is a spring-flowering bulb with strap-like foliage that is planted in the autumn. There are various common names for this ornamental onion, but none refer to what is clearly its most striking feature: The flower head and seed head look like fireworks exploding. While its display is dramatic, there is one serious drawback to growing this plant. But new gardeners will find the plant easy to grow and a welcome addition to the spring landscape.

Botanical Name Allium schubertii
Common Names  Schubert's Allium, Schubert's onion, ornamental onion, flowering onion, tumbleweed onion, Persian onion
Plant Type Spring-flowering bulb 
Mature Size 18 to 24 inches tall, with a width slightly less than that
Sun Exposure Full sun
Soil Type Any average, well-drained soil
Soil pH Roughly neutral (pH 7)
Bloom Time May in USDA zone 5
Flower Color Pink
Hardiness Zones 5 to 8
Native Area Palestine, Syria, northern Iran, and western Turkestan

How to Grow Schubert's Allium

While the plant is listed as being hardy to zone 5, it can be even cold-hardier than that under the right conditions: most notably, a soil that drains well. By contrast, if you have a heavy soil that retains water in winter, chances of survival are decreased. Schubert's Allium may even become naturalized under the right conditions.

Think about the regions to which this ornamental onion is native (western Asia), and that will give you a clue as to the soil it likes: a well-drained soil. Once established, it is a drought-tolerant perennial. In fact, it needs to be in dry soil during the summer, fall, and winter to remain healthy. Planting in a loamy soil enriched with humus results in superior growth.

Schubert's Allium is a spring bulb plant. As with other such bulbs, you must remember to plant it in fall if you wish to enjoy those delightful blossoms in spring. As always when planting bulbs, the height of the bulb, itself decides planting depth. Make your hole three times deeper than the bulb's height. For example, if the bulb measures 1 inch tall, dig 3 inches deep. 

Bulb orientation in the hole is also important. Look for either a point on the bulb or tiny roots. A point indicates the top, roots the bottom. Bury the bulb in the soil so that the top points up. Apply bulb fertilizer in the hole and water it in.

The leaves are not especially attractive—particularly during and after flowering. But resist the temptation to tidy up by cutting the leaves. Messy as they look, they are serving a purpose, taking in nutrients through photosynthesis. So let the leaves remain standing until they turn completely brown.

Divide the plants in fall if necessary.

If you doubt the cold-hardiness of this ornamental onion in your area, mulch it to furnish winter protection.

Light

Install this plant in full sun.

Soil

Most importantly, the soil must drain well.

Water

Water well in spring. For the rest of the year, the plant will not need much water.

Fertilizer

Apply compost anytime. Alternatively, you can apply a bulb fertilizer immediately after Schubert's Allium has finished blooming, as you would with other bulb plants.

Best Feature of Schubert's Allium

The beauty of its flower only begins to tell the story of this remarkable plant. It's really the shape, size, and structure of the flower head, rather than the color of the individual flowers, that is exceptional. It's possible for a flower head to contain 100 or more blooms. While some of those blooms (say about 50) in the flower head remain close to the center, others blossoms (another 50 or so) will be found on long stalks that shoot out to various distances from the center. This is the reason why the flower head is said to look like fireworks "bursting in air."

Some Schubert's Allium plants will produce a flower head forming a globe 18 inches across. Some of the longer flower stalks will be 4 inches long, others 9, still others somewhere in between those figures. A seed head succeeds this flower head and will dry of its own accord, leaving you with a highly decorative, straw-colored sphere of great complexity.

The dried seed head will become disengaged from the stalk and fall to the earth, where the wind will send it tumbling along the ground, releasing seed as it goes. Thus the origin of one of the common names: "tumbleweed onion." The allusion is, of course, to that classic desert plant, the tumbleweed, forever associated with Westerns.

Animals Attracted to Schubert's Allium

A good plant to attract butterflies, Schubert's Allium does not attract wildlife that you probably don't want on your land: deer. Like many strong-smelling specimens (it is a type of onion, after all), it is a deer-resistant plant. So far, so good. The outlook is not so sanguine, however, if you're a pet owner.

Toxicity Warning

Plants in the Allium genus are poisonous to dogs and cats. Do not let pets eat any part of a Schubert's Allium plant.

Uses in Landscaping and Beyond

In spring, Schubert's Allium is spectacular enough to serve as a focal point in a planting bed of small plants. Give it plenty of space, as you do not want the foliage of other plants obscuring your view of it during its peak display time. Consequently, avoid planting it next to large plants which will swallow it up and render it an afterthought in your design—a landscape design mistake. As plants that crave sharp drainage, they are especially useful in rock gardens.

These ornamental onions will also furnish you with good cut flowers, as they are not only stunning but boast a sturdy stem. Even better, enjoy them as dried flowers (the flower heads will dry out without any help from you and hold up quite well). Against a dark background, the dried seed head may actually be more attractive than the fresh flower head.

But, if you own pets, take precautions, or simply abstain from growing the plant altogether. There may be some viable workarounds that will allow pet owners to grow and display Schubert's Allium safely. For example, you can put a fence around the planting bed where you will be growing the plant outdoors. And if you wish to display the cut flowers indoors in a vase, do so only in a secure room that pets are not allowed to enter.