Allium Giganteum

Interested in Growing Allium Giganteum?

What you may recognize as the ornamental “giant onion” is actually termed allium giganteum, and can be a gorgeous addition to any garden. Before running off to buy or plant some giant onion in your garden, you may want to first learn about the specific planting environment your allium giganteum needs in order to flourish.

First, let’s learn a little bit about the plant itself. It is known as a bulbous perennial with bulbs of about three or four inches in diameter. The stem commonly grows to a height of about four feet and is considered a “naked” stalk (meaning it is without the fuzzy hair that many plants have). The leaves attached to the stem are often described as “strap-shaped”, grey-green in color, and just under eighteen inches in length. The flowers of allium giganteum are the most attractive feature, by far! Small star-shaped flowers (that look almost like a skinny version of lilac flowers) grow by the hundreds in the shape of a globe. This globe reaches about four or five inches in diameter and sits singularly on top of the large stem. The stems and leaves produce an onion-like smell when scraped or damaged, but they are not to be used for cooking.

For optimum growth, giant onions need full sun and soil that is between dry and average moisture level. Overly wet soil can result in bulb rot and the death of the plant. One thing to watch out for with this plant is wind damage. Because the stems are so tall, these plants can easily snap on a windy day, forever damaging the plant. In some cases, support sticks may be useful in preventing breakage. These flowers are not self-pollinating, therefore it is important that you plant several of them in order to achieve flowering. A common use for the plant is for bordering or to line fencing, however they are not very suitable to be planted in a pot due to their size and fragility.

The giant onion can survive in temperatures between 40 and 65 degrees Fahrenheit, and it should be planted with a good grade of potting soil. You may want to hold off on using fertilizer until the plant has become “settled” into its new environment. Throughout the year, be sure to water it with warm water when the weather has a dry spell and keep an eye on the acid levels in the rain water. This could harm the plant. Other things to look out for include sagging or drooping of the stem. As mentioned earlier, the height of these plants make them vulnerable so it is important that you regularly check them for signs of stability issues.

If you decide to plant the giant onion from a bulb, you can start it in a planting pot until it becomes large enough to safely plant into the ground. Wherever you plant the bulb, be sure that the bulb is planted just below the surface of the soil. In fact, almost half of it should be showing above the top of the soil. The soil should be fairly loose around the bulb. If it is too heavy or packs in too tightly around the bulb, mix a little peat moss or sand in with the soil.

While the allium giganteum is not considered an easy plant for the novice gardener, understanding the needs of this plant is a great way to heighten your chances of gardening success. This is true for any plant that you intend to grow in your garden. The more you know about a plant, the better you can prepare yourself for the proper maintenance and care of the plant, the more likely you are to see a healthy, flourishing plant!




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