There are various common names for this plant, but none refer to what is clearly its most striking feature. That is because the flower head and seed head look like fireworks exploding, if I were to have the honor of naming the plant, I would include "fireworks" in the moniker. Instead, it goes by such common names as:
- Ornamental onion
- Flowering onion
- Tumbleweed onion (see below)
- Persian onion
- Schubert's onion
Plant taxonomy refers to it as Allium schubertii.
"Onion" appears in the common names because Allium is the genus name for both edible and ornamental onions.
Characteristics, Plant Type for Allium Schubertii
Allium schubertii is a spring bulb plant. As with other such bulbs, you must remember to plant in fall if you wish to enjoy those delightful blossoms in spring.
This ornamental onion reaches a height of 18-24 inches, with a width slightly less than that. Foliage is strap-like. The plant blooms in May in my zone 5 landscape, producing pink flowers.
But that 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 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, in my example) 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."
But let's talk measurements. One of mine produced a flower head forming a globe 18 inches across. Some of those longer flower stalks I mentioned were 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 Missouri Botanical Garden notes that a dried seed head will become disengaged from the clump and "tumble along the ground with the wind spreading seed as they go." 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. Other than my invented common name for this plant (namely, "fireworks onion"), "tumbleweed onion" is perhaps the most descriptive designation.
Planting Zones, Sun and Soil Requirements
I can safely recommend growing these bulbs in planting zones 5-8. I have, however, seen them listed as being even cold-hardier than that. A lot will depend on your soil: if you have a heavy soil that retains water in winter, chances of survival are decreased.
According to Anna Pavord's book on flower bulbs, they are indigenous plants in "Palestine, Syria, northern Iran, and western Turkestan." But they may become naturalized plants elsewhere, under the right conditions.
Think about the regions to which this ornamental onion is native (see above), and that will give you a clue as to the growing conditions it likes: namely, full sun and 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 may result in superior growth.
Wildlife and Allium Schubertii
A good plant to attract butterflies, Allium schubertii does not attract wildlife that you probably don't want on your land, namely deer. Like many strong-smelling specimens (remember, 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 (see below).
The leaves of Allium schubertii 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 in fall.
If you doubt the cold-hardiness of this ornamental onion in your area, mulch it to furnish winter protection.
To fertilize, you can apply compost anytime. Alternatively, you can apply a bulb fertilizer immediately after flowering, as you would with other bulb plants.
Uses in Landscaping and Beyond
In spring, flowering onions such as Allium schubertii and the various purple alliums are 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 of which I was initially guilty.
For a photo of what Allium schubertii looks like when it is covered with pink flowers in spring, see my closeup picture of an ornamental onion.
As plants that crave sharp drainage, they are 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); but see below about taking precautions if you own cats.
More on Allium Schubertii: Attention, Cat Owners!
What's not to like about a plant that boasts all the features I discuss above? That's what I wondered when I first grew Allium schubertii. But experience can be a stern teacher, and I was eventually enlightened as to a potential drawback to this otherwise splendid ornamental onion.
As mentioned above (and illustrated by the photo atop the page), Allium schubertii will be valued by those who like to work with or display dried plant material. Against a dark background, the dried seed head may actually be more attractive than the fresh flower head. So you can just pluck one, stick it in a vase and display it in a suitable corner of your home, right?
Not so fast! Ornamental onions (plus the types that we humans eat) are considered poisonous plants for dogs and cats. We found that fact out the hard way when we brought a dried seed head in from our Allium schubertii planting.
My wife, Maria and I have an indoor cat, and the curiosity of these pets is, of course, legendary. Our beloved feline, Aglaia got into our display, playfully chewing on the seeds. Persistent vomiting ensued. We called her regular veterinarian but were unable to book a timely appointment. The alternative was the emergency animal hospital, which is the much more expensive option.
$1300 later, we were visiting a cat in a hospital cage who had had one of her front legs "poodled" to accommodate an intravenous catheter. But she pulled through.
You cannot put a dollar value on a pet's life, but you can and should think proactively about these matters. Let's say you own a cat that goes outdoors, and you're wondering whether you should grow Allium schubertii in the yard. Are you absolutely certain that you can keep your pet away from it? If not, you need to ask yourself another question...
Do you have an extra $1300 lying around?