Are you wondering whether gladiolus flowers spread on their own or need help? Read this article to find the answer to this question.
Gladiolus is a perennial flowering plant in the genus Gladiolus from the Iridaceae family.
The name “gladiolus” comes from the diminutive of “gladius” from Latin, which translates as “sword,” and which I believe perfectly describes the look of this plant. It is also commonly known as gladiola, or sword lily.
Gladioli are summer plants that are admired by many for their vivid blossom tones, color diversity, and the fact that they are some of the most resistant garden flowers. The common garden varieties can surpass 5 feet in height (150 cm), while the wild species are smaller, reaching between 11 to 20 inches (30-50 cm).
Now that you know a bit about these plants, let’s get back to our main topic.
Do Gladioli Spread?
Gladioli hold the potential to spread on their own if left in the ground and in the right climate conditions. However, this is conditioned by environmental factors, and most often, the plants will need additional help to multiply and expand to larger areas.
Even though gladioli are perennial plants that can survive multiple years when established, they are most of the time grown as annual because are highly sensitive to frost.
To understand how gladioli spread, I think it is important to first understand how these plants multiply.
How Do Gladioli Multiply?
Gladiolus reproduces through a sort of bulbs, called corms. These corms have a flat shape, are covered by scale leaves, and can produce smaller corms, called cormels.
When planted, these smaller corms will grow the first year without producing flowers. In the second year, once they reach maturity, they will start to develop flowering plants and will also start to produce cormels on their own.
Will Gladiolus Survive Winter?
As I mentioned earlier, the biggest issue and the thing that prevents gladiolus from spreading on its own is the frost.
Unlike the tulip bulbs who can withstand moderate winter cold, gladioli are not that lucky. While gladioli can resist a short period of freezing temperatures, they typically will not survive extended winters with a severe cold.
Gladioli may be able to overwinter outside and spread by themselves for more years in some climates. However, it is not possible in many regions.
The cold-tolerance also depends depending on one gladiolus variety to another. The smaller types seem to resist better to lower temperatures than the larger varieties.
Another danger of leaving the corms in the ground for the areas with no frost, but heavy-rain winters is that this can make them susceptible to rot, fungal problems, and other diseases.
The easiest and safest way to ensure that you can still enjoy these plants the upcoming year is by digging the corms out in late fall and keeping them in a dry and frost-free place during winter. You should then plant them back in your garden in early spring after the frost passes.
Gladiolus corms are typically planted outdoors from late March to late May, but this can vary from one climate to another.
The corms should be planted at approximately 4 inches deep (10 cm), at a distance of about 7-11 inches (20-30 cm) between each other.
Gladioli grow best in sandy loam soil with sufficient water drainage. Add a layer of compost to improve soil’s water drainage and improve fertility.
A gladiolus needs between 80 and 100 days to bloom.
When To Dig Up Gladiolus Corms?
One of the biggest mistakes most gladiolus lovers make is digging up the bulbs too early.
As with other bulbous flowers, gladiolus corms should be removed only in late fall, after the full foliage of the plant is dead (not wilted, but thoroughly dried). That should be generally after the first early frost.
Dig up the gladiolus corms gently, leaving the dried stalks still attached to them (removing them at this time might hurt the bulb and leave them prone to rot). Also, do not separate the tiny cormels from the primary bulbs yet.
Remove the soil leftovers and store the bulbs and the connected leaves for 1-2 weeks in a space protected from moisture, at a temperature between 68-86°F (20-30°C).
Only after the corms are completely dry, you should remove the dead foliage and separate the small cormels from the central corm.
Because they are perennial, gladiolus bulbs can spread by themselves and expand if they have the right climate conditions to survive over winter.
Yet, these requirements are many times impossible to deliver, and unless you plant the gladioli in pots and keep them indoors, you have to dig up the corms before the frost and replant them in the spring.