How to Grow and Care for Gladiolus Flowers

Gladiolus Flower Plant

About Growing Gladiolus Flowers in Your Home Flower Garden

Gardeners and homeowners love growing gladiolus plants in their flower gardens. Growing Gladiolus flowers from corms is easy. It is a beautiful summer flowering plant. It blooms in mid to late August, just as many other flowers cease production. And, they are an attractive and stately flower. Gladiolus plants are known by several other names, including Gladiola, “Glads”, and even “Sword Lilly”. Why Sword Lily, you might ask? It’s because of their long, sword-like leaves. But, Glads are not members of the Lily family. Whatever you like to call them, their showy spikes make them one of the more popular flowers grown in the home flower garden.

Gladiolus flowers are native to the mountains of South America. They are widely grown in the U.S. and Europe.  They make for a beautiful, stately flower in the garden and floral arrangements, hence their popularity.

With just a little attention, your glads will burst into a bloom of tall spikes in July or August. Blossoms come in a wide range of colors and bi-colors, including blue. The blossoms will open from the bottom first. Harvest spikes of Gladiolus just before the top blossoms open. The top blossoms will open indoors.

Did you know? You might think that Gladiolus grows from bulbs….wrong! They actually grow from a closely related cousin, the “corm”. See more on Bulbs, Corms, and Rhizomes.

Toxicity: The corms and parts of the plant are toxic.

Flowers Bloom: Mid to Late Summer

Flower Colors: There’s a wide variety of colors and bi-colors.

Plant height: 2 to 5 feet tall.

Plant Hardiness Zones: 8 – 11

Gladiolus Flower Plant Propagation

Plant the corms a few weeks after the last expected frost date in your area.

Gladiolus flowers look their best in groups. And their height makes them good candidates for the back of the flower garden. Dig holes about 6-8 inches deep, and six inches apart. Some people find it easier to dig trenches in a straight line, an arc, or another pattern. 

Add bulb fertilizer or bone meal into the holes as directed on the fertilizer package.

Next, cover the corms with soil. 

Water the planting site. Then, keep the soil moist.

Now the wait begins. Your Glads will bloom about 70-100 days after planting the corms.

Tip: If you are planning a color-coordinated design for your flower garden, sort corms by color, before putting them away.

Bulb Planting Depth: Plant the corms 6 to 8 inches deep with the root side down.

Final Plant Spacing: 6 to 8 inches apart. They tolerate a little crowding. However, plants and flowers are smaller when overcrowded.

How to Grow Gladiolus Flowers

Select a planting site that receives full sun. However, Gladiolus will still grow well in partial shade. My glads receive full morning sun before being shaded by the house in the afternoon. 

Gladiolus plants grow best in rich, well-draining soil. A little fertilizer helps to stimulate growth, especially if the soil is poor.

Plant Gladiolus in the spring. They can be grown in rows or bunches. They will tolerate a little crowding but will grow bigger if spaced out. 

Once planted, your gladiolus should grow well with little attention. Add mulch to help retain water, and to keep the weeds down.

Gladiolus will grow two to five feet tall. But, they are not sturdy plants. The heavily flowered spikes are susceptible to bending and breaking. Protect from the wind, if possible. Tie the spikes to plant stakes, to avoid wind damage. Also, mound soil around the plants after they have grown at least six inches tall. This provides the plant with additional support.

After the plants have died back in the Fall, cut the plants back to the ground. In colder regions, cover the area with a thick layer of mulch to protect the corms from freezing.  

Ideal Soil pH: 6.0 – 7.0.

Did You Know? Gladiolus corms were once used to remove thorns and splinters.

Winter Storage

You’re probably well familiar with bulbs, which reproduce baby bulbs below the mother bulb. Corms, on the other hand, produce new corms on the top of the mother corm.

In colder regions of the country, a thick layer of mulch may not be enough to protect gladiolus corms from freezing soil. So, it is best to bring them indoors. Here’s how to store them indoors over the winter months:

  1. First, Remove the plant to an inch or so from the top of the corm.
  2. Next, dig up the corms and brush excess dirt off of them.
  3. Separate the corms.
  4. Then, allow them to dry for a week.
  5. Place the corms in a paper bag.
  6. Finally, store them in a cool, dark place in an area that is not too humid. High humidity can cause mold to form on the bulbs and ruin them.

Insects and Plant Disease

Insect and plant diseases are uncommon. However, Thrips can be an occasional problem. Use insecticidal soap to eliminate them.

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