How to Grow Gladiolus Flowers in Your Garden

How to Grow Gladiolus Flowers in Your Garden

Gladiolus are magnificent flowers that add elegance and structure to a garden. Additionally, you can cut gladiolus and arrange them in your flower vases or combine them with other flowers in the vases to bring rich colors to your spaces.

Also, these flowers have a fantastic texture and come in different beautiful colors (yellow, white, hot pink, garnet red, coral, green, and cream). 

And yes, you can grow these flowers in your garden – it’s very easy – with the right care and environment, they will thrive!

So, in this article, we shall discuss everything you need to know about growing gladiolus: history, how to grow gladiolus, plant care, harvesting, storage, and pests & diseases.

Types of Gladiolus

Besides these flowers featuring different colors, they can further be classified into two groups: large-flowered and miniature. Let’s see each of these classes briefly:

 

Large-flowered

These are the most popular of all gladioli. These types have large flowers, have one-sided spikes and the florets face the same side. 

These large-flowered gladioli are best used in cut flowers or in exhibitions. 

Additionally, the petals of these flowers are ruffled, semi-ruffled, frilled, or plain. Also, these flowers feature almost all colors of gladioli.

History of Gladiolus

Types of Gladiolus

Besides these flowers featuring different colors, they can further be classified into two groups: large-flowered and miniature. Let’s see each of these classes briefly:

 

Large-flowered

These are the most popular of all gladioli. These types have large flowers, have one-sided spikes and the florets face the same side. 

These large-flowered gladioli are best used in cut flowers or in exhibitions. 

Additionally, the petals of these flowers are ruffled, semi-ruffled, frilled, or plain. Also, these flowers feature almost all colors of gladioli.

Large-flowered

Miniature glads

Miniature glads are the opposite of large-flowered glads; they have short petals and spikes. But, these smaller versions of glads are patterned just like their large-flowered cousins.

Additionally, miniature gladioli are suitable for a small flower arrangement.

Miniature glads

Gladiolus Bulbs

A gladiolus bulb, also known as a corm, is an underground stem or a food storage structure that supports plant growth. 

The functions of the corms were witnessed in the gladiolus that natively grew in South Africa during dry seasons. During these dry periods, the corms kept the plants alive until the spring rains, when the plants would thrive.

Additionally, it’s interesting how glads develop; each year, a new bulb develops on top of the old one while the old one withers and dies. 

Buds then develop on the surface of the new gladiolus corm while the bases of old leaves, also known as husks, cover the corm.

In addition, new small corms (cormels or cormlets) form at the base of the main new cormel, as you will see in the diagram below. These cormels can help you in propagating your desired glad types.

Gladiolus Bulbs

Selecting Corms

Healthy gladioli corms produce vigorous plants and flowers with maximum sizes for each variety. 

But how will you know whether your corms are healthy? It’s simple – look at the husks – they should be smooth and not damaged or discolored. 

Also, the corm should be firm, and when you remove the husks, there should be no dark areas or spots on the surface of the corms. Additionally, the base of the corm should be firm and well-healed.

Selecting Corms

Defects

Damage

Serious Damage

Bacterial spot

Aggregating more 3/8 inch in diameter on a 1-inch diameter corm and correspondingly greater or lesser in larger or smaller corms

Discoloration

Aggregating more 3/8 inch in diameter on a 1-inch diameter corm and correspondingly greater or lesser in larger or smaller corms

Cuts

Aggregating more than ½ inch in length and 1/8 inch in depth on a 1-inch diameter corm and correspondingly greater or lesser in larger or smaller corms.

Bruises

Aggregating more than ¾ inch in diameter in a 1-inch diameter corm and correspondingly greater or lesser in larger or smaller corms.

Thrips

When there are the thrips or evidence of thrip feeding on corm

Nutsedge

When present or penetrates the surface of the corms

Grassroots

When they have penetrated the corm surface

Decay

Soft, mush, or disintegration of some tissue on corm

Mold

When it has affected the root system or has penetrated the corm surface

Shattered

When corms are split, crushed, or cracked

Freezing

When corm is frozen or soft after freezing

Source: USDA

Gladiolus Gardening Tips

Let’s see a number of tips that will guide you when growing and caring for gladioli.

 

Soil 

Gladiolus is not super picky when it comes to soil holding its roots. But if you still want to choose the best soil for these plants, go for loam or sandy loam.

Here are more soil needs and tips for this plant:

  • A soil PH between 5.5 to 6.5 and medium soil fertility will be great for glads (you can do soil tests if you are not sure of your soil’s PH and fertility and improve it if necessary)
  • If your soil ‘produces good vegetables, it can produce good glads too
  • You can add organic matter (e.g., peat moss, compost, or sawdust) to the soil if your soil is not well-draining. But if you use sawdust, ensure you add some ammonium nitrate since sawdust ties up nitrogen in the soil.
  • Glads don’t do well in poorly drained places – raised gardens can be a great option for growing glads in such places
  • To improve the fertility of your garden, add 2 pounds of 5-10-5 fertilizer per 100 square feet of your planting space. 

Spread the fertilizer evenly on the soil surface, then dig the soil 6 to 8 inches deep to mix the soil with the fertilizer.

Also, you can use well-rotted cow manure with your glads, and just like fertilizer, dig the manure into the soil to prevent bulb rots.

 

Planting

Select a good location for planting gladiolus seed: a place with good drainage and full sun access (away from shades of other tall plants, trees, or buildings).

Plant your corms about two weeks before the last expected spring frost. These plants often take 70 to 90 days from planting to flowering. 

Also, you can plant gladiolus corms in intervals of two weeks until early summer if you would like to have a continuous harvest of gladiolus flower spikes. 

Plant the corms 2 to 6 inches into the soil depending on the corm size and burry with 2 inches of soil. Remember to plant the corms 5 inches apart and space the rows at 20 to 36 inches.

Once your plants are about 6 to 10 inches tall, add more soil around the base to support the growth of the stems.  

 

Cultivation

Cultivate your gladioli garden to keep weeds and grass from competing with your plants. But esure you cultivate shallowly to avoid damaging the roots of your plants.

In addition, you can use a mulch to suppress weeds and preserve soil moisture in your glads garden. The suitable mulches to use with glads include sawdust, straw, and wood shavings. Remember to apply a little nitrogen after a heavy mulch application.

Also, herbicides are another option for eliminating annual weeds and reducing the need for cultivation.

 

Watering

Like many other plants, glads require enough water to thrive during an entire growing season. 

That said, water your glads weekly during the dry weather days. Ensure you thoroughly water the soil holding your plants and avoid daily light waterings.

 

Staking 

You will need to stake your glads for them to grow tall and have straight flower spikes. 

The best time to add stakes in your glads garden is after preparing the soil and just before planting the corms; this will ensure you don’t pierce the corms later with the canes. 

So, when the glads attain a  reasonable height, tie them to the stakes with soft twine or cloth stripes at intervals of 10-inches. 

Remember not to tie the glads tightly on the canes – leave a little space in between to allow the stems to expand freely.

Gladiolus Gardening Tips

Fertilizer side-dressing

Side-dressing your plants when they are already established will increase their vigor. Apply a 5-10-5 fertilizer on the soil, 4 to 6 inches away from the stems, and rake it lightly into the soil. 

You can apply the first side dress when the plants are about 6 to 10 inches tall and the subsequent application when the flower spikes start showing.

Apply one pound of the side dress fertilizer per 100 feet on each application. Applying too much nitrogen during the early stages of your plant’s growth can lead to excessive growth of foliage and low-quality flowers. 

 

Cutting flowers

As I mentioned, most people grow gladioli to cut them later for decorative purposes. On that note, remember to cut the flowers during their prime periods for longer stays indoors.

After cutting the spikes, place them vertically in water immediately to keep the petals from withering. 

Here are some more tips to ensure you cut the flower spikes the right way:

  • Cut flowers early in the morning or late in the evening and not when it is hot
  • Carry a sharp knife and some lukewarm water in a bucket to the gladioli garden
  • Cut the spikes that have only one or two open flowers – the unopened flowers will open later in the vase
  • Cut the flower spikes diagonally and place them in the bucket
  • Ensure you leave at least four leaves on the gladiolus plant to allow the corms to properly mature if you would like to reuse them
  • Place the bucket with your flowers in a dark, cool place for a few hours before arranging the flowers in a vase
  • Remove the flowers fading at the bottom of the spikes and cut one inch of the stalks bottoms every few days.

 

Digging up and storing corms

You can dig out the corms when the blooms are over and when the tops die off. Also, you can dig them out before any hard freeze. 

Additionally, it would be best to leave healthy plants on the soil to allow the corms to mature fully.

Here is how you dig up and store your gladioli corms:

  1. Dig up the entire plant using a spade while ensuring you don’t bruise the corms
  2. Shake off the soil from corm roots and throw away damaged corms. 
  3. Cut the flower stalk 1 to 2 inches above the bulb. You can save the small cormlets separately if you want it that way.
  4. Place the corms outside under the sun to dry for 1 to 2 days
  5. Sift out excess soil from the corms and place them on a flat wooden tray
  6. Cure the gladioli corms in a dry, airy place at a temperature between 27°C to 29°C (80°F to 85°F).
  7. Remove the old corms from the new ones and throw them away. Remember not to remove the husks from the corms.
  8. Dust the corms with an all-purpose garden fungicide; this is to protect the corms against pests and diseases while in storage.
  9. You can store the corms during winter in a well-ventilated room that has temperatures between 35°F – 45°F. Airy containers like mesh bags make great storage bags for corns. You can then hang your packaged corms.

Another thing to remember here is that you should not freeze the corms.

 

Pests

Gladioli will rarely be affected by pests, but if they do, it just has to be thrips. 

Gladiolus thrips are tiny; you might not see them easily since they hide and feed in hidden places. These insects do considerable damage to glads, especially to flowers.

To keep your plants safe from thrips, mix one tablespoon of Lysol household cleaner with a gallon of water. Then, soak the corms in this solution and plant the corms while still wet.

Also, you can plant different flowers in your garden. These flowers will attract beneficial insect predators that will feed on thrips. 

Other pests that can bring trouble to your glads include aphids, cucumber beetles, and grasshoppers. 

 

Diseases

Different diseases can affect gladioli bulbs and stems. Generally, these diseases are called corm and stem rots. Most of these diseases result from poor curing and storage.

So, before you plant your corms in spring, thoroughly inspect them; pull off the husk a bit and see if the corm surfaces are infected. Discard infected corms since they will produce weak plants and plants that are vulnerable to stem rots.

Conclusion

I believe the above guide on how to grow gladiolus has been of great help to you. So, go through every tip we have discussed and apply it in your glad garden. And in a few months, the elegance of gladioli will arrive in your spaces!

But, if you can’t find corms in your area to start your gladiolus flowers, don’t worry; you can consider other pretty alternative flowers. In this case, check out my next article: Hydrangea Vs Azalea: Which One is Best for Your Garden?

Resources

  1. Summer Flowering Bulbs: Gladiolus
  2. Grading Gladiolus Corms 
  3. USDA Plant Hardiness Zone Map
  4. USDA Grades of Gladiolus Corms
  5. Model Profile of One Acre Gladiolus Cultivation
  6. Evaluation of Gladiolus
  7. Effects of Different Planting Dates on The Development of Glads
  8. Commercial Cut Flower Production; Gladiolus
Robert Silver

Robert Silver

Robert Silver is a writer, speaker and certified master gardener who has been sharing his landscaping experiences through personal blogs. Taking it to the next level, Robert Silver has come up with this progardeningblog.com to shine a light on new planters and experts, discussing plants, landscape projects and much more. He has published numerous research articles on horticulture that have helped many people attain fruitful outcomes.