A Guide On How Deep To Plant Gladiolus

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Last Updated on January 9, 2023 by Urska

One of the most researched questions is how deep to plant gladiolus, with gardeners wanting to know the actual depth to bury these corms.

These traditional flower spikes have been blooming all across America in midsummer and used extensively in bouquets.  A gladiolus is every gardener’s favorite due to its flowers, colors, and height.

The most popular gladiolus grows up to 3 to 4 feet tall and comes in a wide range of colors – hot pink, garnet red, cream, yellow, coral, and even green.  Most gladioli are winter hardy to USDA zone 7 with one exception of Gladiolus nanus. This type is winter hardy to USDA zone 5, featuring 20-inch tall plants on corms.

You can grow these flowers together with lavatera, zinnias, and celosia to have a more attractive garden.

How To Plant Gladiolus Bulbs

It is essential to know what planting conditions are suitable for this plant.  They include

  • Soil.  Gladiolus thrive in rich, well-drained, sandy loam soil. If the soil is too heavy and wet, the corms will rot.  If your soil is clay, grow them in raised beds with loosened soil up to 12 inches deep before planting.
  • Light:  These plants prefer full sun when growing and blooming.  Gladiolus corms can also flower in the shade, but the colors are not as vivid as when grown under full sun.  Also, if grown under the shade, the plant won’t grow quite as well.
How To Plant Gladiolus Bulbs
  • Spacing: Space the gladiolus corms at least 6 to 10 inches apart in the garden.
  • Planting: Plant your gladiolus corms in spring, 2 weeks before the last expected frost date. To enjoy the flowers all summer, plant them every 2 weeks until early July. This will stagger both the plantings and flowering times. You can also extend your flower season by growing early, mid and late-season varieties.

How Deep To Plant Gladiolus Bulbs

You can plant gladiolus weeks before the last day of expected spring frost.  It takes them 70 to 90 days from planting to harvesting flower spikes.  Plant a few corms every two weeks until summer begins if you want a continued harvest of flower spikes.

So how deep do you plant gladiolus bulbs?  Plant your bulbs at 2 to 6 inches deep, depending on their size, and cover them with 2 inches of soil.

When the plants get to 6 inches, hill up the soil around the base of the plant to help support the stem.

Caring For Gladiolus


When your plants produce about 5 or 6 leaves, support them. Bamboo canes are the best and use the yard to tie them to the support loosely. Don’t tie too tightly as it will strangle the developing flower head.  Ensure that the stakes are inserted away from the base of the plant to avoid damaging the corm.


Water your plants during any periods of prolonged dryness to prevent the soil from drying out.  A good watering every once a week is the best way to water these plants. When growing them in containers, you will need to water them daily.


Feed your plants with a liquid fertilizer every fortnight to help promote vigorous growth.  Once the flower spikes develop, switch to a high potash fertilizer.


Gladiolus doesn’t like growing among wees, therefore weed before planting these flowers. To preserve the soil moisture, mulch the plants after they emerge from the soil with a 2 or 3-inch thick layer of straw or bark mulch. The mulch helps to keep the weeds from growing again once you have planted gladiolus.

Lifting And Overwintering

Most varieties are not completely hardy, so you will need to lift the corms and store them throughout winter.  You can try leaving them in the ground with a thick mulch over the soil in mild parts of the country.  However, it could be a risk.

Dig your corms after the first frost and let them dry for a few weeks before storing them. Once dry, detach them from the older mother corms and store them in boxes or mesh bags. Here is how to prepare for lifting and storage.

5 Gladiolus Blue Color Flower Bulb Perennials Summer Plant

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  • Cut back the foliage to the ground and dig the corms once the leaves have started to yellow.
  • Leave the corms in a warm, airy, and dry area away from direct sunlight to dry for about 3 weeks.
  • Once dry, knock off the soil from the corms.  Remove and discard the old bottom corm. You will notice small cormlets attached to the new corm, remove them too and discard them.  Keep only the largest ones about ½ inch in diameter.  These stored corms will serve as the seed for the next season.
  • Store the ready corms in mesh bags in a well-ventilated, dark room where temperatures range between 35F and 50F.

Pests And Diseases

Gladiolus is infested by thrips that feed on the flowers and leaves, causing characteristic streaking and discoloring.  Thrips could overwinter with corms, so it is best to treat your corms before storing them if they have infected your plants. Treat them by dipping them in boiling water for 2 minutes to kill thrips. Ensure that you dry them well before storing them. If you cannot treat them, discard them and buy new ones in the next season.  To eliminate thrips during the growing season, spray your gladiolus plants with Neem Oil or insecticidal soap to kill them.

Discard any rotting corm before planting as it could carry a bacterial disease that could infect your soil. Remove and destroy any plant that shows signs of viral diseases.


If you love growing gladiolus, you can cut blooms for bouquets.  Cut the flower spikes on a slant when the lowest flowers on the stalk begin to show color. Leave at least 4 leaves on the plant to feed the corm for next year’s blooms.

Harvesting Gladiolus

Place the cut end of the flower spike in water immediately after cutting.  Then you can enjoy having them on your table or window to bring your home to life.


We have provided you with a guide on how deep to plant gladiolus and everything else to grow these plants. Have a fulfilled gardening, won’t you?

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