How to Grow Gladiolus — Add a Burst of Color to Your Garden!

Sharing is caring!

Do you want to add a burst of color to a smaller garden? The iconic gladiolus is the perfect plant for you.

It grows tall and has roots that don’t need to spread wide, making it ideal where space is an issue.

It can be grown in beds, raised beds, borders, and patio containers.

Gladiolus is perfect for formal, informal, cottage, traditional, and courtyard-style gardens. 

The beautiful gladiolus is easy to grow, not fussy, and will reward you with stunning colors. 

Another name for Gladiolus is Sword Lily, named for its sword shape that offers tall spikes. There are many cultivars and hybrids, each with its own unique colors and attributes. 

From red to pink, purple, white, magenta, and yellow, you can decide on the color tones you want to show off in your garden.

If you enjoy getting your fingers into the soil more often than not, you can plant sword lilies corms every two weeks, and extend their colorful display through the summer. 

Let’s look more closely at how to create the ideal conditions for growing Gladiolus. 

 

Gladiolus Care

Plant Gladiolus in full sun, 6 to 8 hours per day. The soil must be humus-rich, moist, and well-draining. Temperate conditions are preferred. Water regularly during the growing season when shoots first emerge. Bulbs should be dug up and stored for the winter season. 

 

Soil

Gladiolus enjoys humus-rich, well-draining soil with medium moisture. This plant is very adaptable to chalk, loam, and sandy soil. It does not do well in clay soil. PH levels are not vital, soil can be neutral, slightly acidic, or slightly alkaline. 

To get the most vibrant, colorful, strong, healthy flowers, it is always best to plant your Gladiolus into the soil type that makes it happiest. 

In this case, it is humus-rich, well-draining, medium moisture soil. 

Humus-rich soil is a dark color and is filled with organic material created from decaying plants.

If you don’t have natural humus-rich soil in your garden, you can create it in a home compost bin, or eco-composter.

These bins are filled with food and garden scraps, that are then broken down into a rich compost. 

If you are not up to this, purchase some rich soil from your farmer’s market and dig it into the ground before planting your gladiolus corms. 

Medium moisture soil means that the soil should stay damp during the growing season. Do not allow it to dry out. Once the flowers bloom, you can reduce your watering. 

When it comes to the type of soil, gladiolus is very tolerant. It will grow in sandy, loam, and chalky soil. The only soil type that it is not happiest in, is clay-type soil. Clay-type soil is not well-draining, and gladiolus requires well-draining soil.

Water should not accumulate at the roots of the plant. This will cause them to rot and make your plant more susceptible to root rot and other diseases. It may even eventually die. 

Drainage can be improved by adding perlite or peat to your soil. You can also dig in some crushed granite to allow water to run out more easily. 

It is useful to know the PH levels of your soil. This is an indication of how acidic or alkaline your soil is. Readings of under 7.0 indicate acidic soils. Readings over 7.0 indicate alkaline soils. 7.0 is the neutral value. 

As most gladiolus plants are tolerant of both acidic and alkaline soil, you need not worry too much about this. 

 

Light

Gladiolus enjoys full sun. That means at least 6 hours per day and preferably 6 to 8 hours per day. South-facing gardens are ideal as they get all-day sun. Some varieties are more tolerant of shady conditions and will grow in partial shade. These varieties can be planted in west-facing gardens that get hot midday and afternoon sun. 

Sword lilies flourish best in full sun. Some varieties will tolerate partial shade. 

Full sun is at least 6 to 8 hours per day, with no shade. South-facing gardens are ideally suited as they get sun all day long. West-facing gardens get sun from midday through the afternoon, also making them an option. 

Unfortunately, east and north-facing gardens will not get enough direct sun to make your gladiolus happy. 

Keep in mind, even though you have a sunny garden, the spot you choose may get shade from other plants, walls, structures, or fences. Take some time out and keep an eye on your garden to find the sunniest spot you can to plant your gladiolus.

 

Watering 

Gladiolus plants love water. Keep them moist through the growing season. Give at least 1 inch (2.5cm) of water weekly. Ensure that the soil does not dry out, but is not water-logged. After flowering, watering can be reduced. In very hot dry weather, continue watering weekly. 

You need to provide consistent moisture during the growing season. That means you will spend some relaxing time in your garden with a hose or watering can. A great reason to get on those gardening gloves and get into the fresh air.

Keeping your soil moist can also be aided by adding a thick layer of mulch around the base of the plant. Plan to make a layer that is at least 2 inches to 3 inches (5cm to 7.5cm) deep. 

Mulch is a natural organic material, made up of a variety of components including shredded bark, kitchen scraps, hay, straw, sawdust, animal manure, and even old newspapers. You can buy mulch from your local nursery or farmer’s market. 

Plan to give your plant around 1 inch (2.5cm) of water per week during the growing season. After the plant has flowered, you can reduce your watering, provided that your soil does not dry out completely. 

The type of soil you have in your garden also affects your watering. Most rules apply to average soil. Very sandy soil requires more water as it runs out much faster. Clay-type soils hold water for longer and can result in over-watering. 

 

Temperature 

Gladiolus prefers a mild climate. They are not tolerant of dry desert or hot rainforest-type environments. Best growth occurs in daytime temperatures between 50°F to 77°F (10°C and 25°C) and night temperatures of around 60°F (16°C). After the first fall frost, corms should be dug up and stored. 

Gladiolus plants enjoy a mild climate. They do best in daytime temperatures of 50°F to 77°F (10°C and 25°C) and night temperatures of around 60°F (16°C).

Some varieties can tolerate occasional temperatures up to 104°F

(40°C), provided that the humidity is higher and the soil is very moist. 

Don’t think desert and don’t think rainforest! These climates are not suitable for gladiolus. 

After the first fall frost, it is time to spring into action. You need to dig up your bulbs and store them away for next spring.

If you live in very cold climates and don’t do this, your bulbs will freeze and may be fatally damaged. They will then fail to bloom in the growing season. 

 

Humidity

Gladiolus thrives best in average humidity. This means a range of 30% to 50% humidity. Very dry, desert-like climates are not ideal. Very moist, damp rainforest-type climates are also not ideal. 

Gladiolus thrives best in climates with average humidity. They are best suited for USA hardiness zones 8 to 10. 

If your climate offers dry desert-like conditions, or moist, damp rainforest-type conditions, browse our blogs for a choice of beautiful plants that are better suited to your garden.

 

Fertilizing requirements 

Gladiolus plants enjoy a balanced fertilizer. Look for indicators that read 10-10-10 or 5-10-10. Overfeeding with nitrogen can damage the bulbs and result in fewer or no flowers. Add liquid fertilizer into your hole before planting corms. Fertilize newly emerged shoots sparingly in spring.

Gladiolus does not require a strict fertilizing routine. You can fertilize after you see the new shoots emerge in spring. 

When choosing a fertilizer for your gladiolus, look for a balanced liquid fertilizer with readings of 10-10-10, 5-10-10, or 5-10-5. These numbers are an indication of the ratio of nitrogen, phosphorus, and potassium in the mixture. 

Gladiolus plants do not want a lot of nitrogen. It can burn the corms and result in no flowers being produced. You can see from these indicators that the nitrogen level, the first number, is not high. 

Fertilizing is important when planting your corms into the soil.

Place some into the bottom of your hole and ensure that it is mixed with soil. Raw fertilizer on the corms will burn them. 

Once the new shoots emerge, fertilize lightly with a liquid fertilizer once or twice in spring. After that, you should not need to fertilize again. 

Adding mulch to your soil is great for gladiolus plants. It helps to retain moisture and also provides loads of natural organic nutrients that will ensure strong and healthy plants. 

If you love fertilizing, you can always dig in some organic compost from time to time to enrich the soil. But don’t overdo it. 

 

How to best use your gladiolus 

Gladiolus is a colorful plant offering flowers through the summer and into fall. Plant in beds and borders. They are ideal for any garden type from informal to cottage, traditional, city, or landscaped. They make wonderful cut flowers to show off in vases. 

Gladiolus offers a stunning show of colorful flowers through the summer and sometimes into fall. Different varieties offer pink, purple, yellow, white, coral, and red blooms.

They are ideal for south-facing and west-facing gardens that get 6 to 8 of full sun per day. 

Some varieties will tolerate partial shade, but try to look for a spot that is sunny. 

Plant your gladiolus into beds and borders. They can grow up to heights of 2 feet (60cm) to 6 feet (1.8m). The taller plants look stunning as a backdrop behind shorter, more compact plants. 

Taller varieties may need to be staked, or supported on fences or trellises until they become strong enough to stand alone. 

Gladiolus is your ultimate cottage-style garden flower. They are also ideal for traditional, courtyard, informal, and in-city gardens. 

Many people love to have gladiolus in pots and containers on patios. They add a burst of color and fun to any outdoor breakfast nook, tea area, or garden hide-away. 

Cut gladiolus flowers look stunning in bouquets in vases. Add a touch of nature to your indoor living space with these delightful flowers. They are known for their long-lasting cut flowers which can last in a vase for 6 days or more under the right conditions. 

 

When to plant your Gladiolus

Corms are planted in spring after the frosts have passed. This follows the resting time of storing the corms away for the cold winter season. Best temperatures for planting corms are around 55°F (13°C). You can plant corms every 10 days or so, to ensure a continuous, long blooming season. 

Gladiolus are somewhat different from many plants in that they are planted from bulbs, also known as corms. 

The best time to do this is in the spring after the frosts have passed. Wait until the temperatures reach above 55°F (13°C).

Avid gardeners enjoy planting corms in batches every 10 to 14 days. This will ensure an ongoing flowering cycle, through the summer and into autumn. 

 

How to plant your Gladiolus corms

After the frosts in spring, you can plant your stored corms. Plant into humus-rich well-draining, moist soil. Fertilize your hole or add compost. Plant corms with pointed-side up, at a  depth of 4 inches (10cm). Space them 8 inches (20cm) apart. Water well and add a layer of mulch on top. 

The planting step follows the period of storing the corms away for the winter season. You can read about that in my section dedicated to storing corms.

When spring arrives, it is time to take your corms out of storage and get planting. 

Choose a sunny spot that will get at least 6 to 8 hours of direct sun every day. Ensure that your soil is moist, humus-rich, fertile, and well-draining. 

Using a garden fork, loosen the soil to a depth of around 12 inches to 15 inches (30cm to 40cm). 

Mix in a layer of mulch, organic compost, or manure. 

You can also choose to add in some balanced fertilizer. Look for fertilizers that are not heavy on nitrogen. A good balance is a 10-10-10, or 5-10-10 combination of nitrogen, potassium and phosphorus. Ensure that the fertilizer is well-mixed into the soil, if not, it can burn the corms and they won’t grow. 

Choose corms that are at least 1/4 inch (1/2cm) in diameter. These will give rise to large blooms. 

Place the corm pointed-side up into the hole, at a depth of around 4 inches (10cm). Larger corms can be planted deeper and smaller corms can be planet shallower. Cover with soil and press firmly down.

Add a layer of mulch on the top of the soil and water well. 

Space your corms about 8 inches (20cm) apart, to give them space to grow. The roots do not spread but rather grow downwards, so they are ideal for smaller gardens where space is limited. 

Grouping corms in batches of 6 to 8, will result in a fabulous, vibrant visual display when they are in full bloom. 

Many gardeners enjoy doing staggered planting. They plant corms every 10 to 14 days to create ongoing blooms. 

 

Gladiolus Growth

Gladiolus grows tall and straight, offering stunning lily-like flowers in many colors. They bloom through summer and some varieties bloom into the fall. In winter, the bulbs either remain dormant in the ground in warmer climates, or can be removed from the soil and stored. 

Gladiolus plants come in a myriad of varieties. Some grow as tall as 6 feet (1.8m), others only reach heights of 2 feet (60cm). 

They grow upright and offer large colorful blooms on strong stalks. Flowers bloom in colors that can be yellow to coral, pink, red, white, and purple. Flowers range in size from a few inches to 10 inches (25cm) in width. The leaves are sword-shaped and dark green. 

Gladiolus plants take up less space due to their narrow, upright habit. This makes them ideal for beds, borders, and containers. 

The corms are planted in early spring and shoots will start to emerge within 10 to 12 weeks from planting. Tall plants may need staking to help keep them erect until they grow strong enough to stand alone. 

You can also plant your corms into containers and create a beautiful display on a porch, patio, or balcony. 

 

Pruning your gladiolus 

Gladiolus plants do not require regular pruning. Pruning can be done after the bulbs are removed for storage in winter. Cut the stalks down to leave only 1 inch to 2 inches (2.5cm to 5cm) above the corm. 

Gladiolus plants do not require pruning. They grow tall and straight and most often than not retain their shape. 

If you notice a stem that is damaged or diseased, you can remove it carefully with a cutter. Using shears is not a good idea, as they will certainly damage your plant and chop off far too much. 

Once you have removed your bulbs from the ground, you need to trim the stalks down to around 1 inch to 2 inches (2.5cm to 5cm) above the corm. Do this before storing them away for the winter season. 

 

Winter protection for your gladiolus

In very cold climates, corms should be removed from the ground and prepared for storage. This will ensure that you can replant them in spring. In warmer climates, you may be able to cover the ground with hay or straw to protect them through the winter. 

Avid gardeners know that gladiolus bulbs, or corms, need to be protected from the cold winter conditions. 

This is something I learned from a friend. At first, I was a bit taken aback that she suggested I dig up the corms and store them away. It sounded like a lot of hard work. 

But, I did the right thing and saved my bulbs for replanting the following year. It was a rewarding experience. 

If you live in cold USDA hardiness zones of 7 or colder, you need to wait for the first fall frost and watch for the foliage to fade. The light frost kills the foliage, but not the plant. That is the time to start digging. 

Use a medium-size spade and dig around the plant to loosen the soil. Then dig underneath, grip the top and pull it gently out of the ground. 

Take care not to damage the corm. 

Shake off excess soil. If the corm appears to be damaged, or diseased, discard it. You can see these easily as they will have soft, mushy spots. Don’t wash the corms as you need to keep them as dry as possible. 

Cut off the stalks, leaving only 1 inch to 2 inches (2.5cm to 5cm) above the corm. 

Place the corms into the sun if possible for a couple of days to dry out. If your weather is wet, allow them to dry in a garage or garden shed. 

Allow them to stand, or cure, for around 2 weeks in a warm, well-ventilated spot. Ideal temperatures for this are 80°F to 85°F (27°C to 29°C). 

You can now dust the corms with an organic anti-fungal powder. Place the corms into wooden trays, cardboard boxes layered with newspaper, paper bags, or even cloth bags. 

Store at 35°F to 45°F (2°C to 7°C). A cool garage or basement is ideal. The vegetable compartment in your fridge is fine, but your freezer will be too cold. Ensure that no one in the family thinks that these are veggies to be cooked and eaten! They are poisonous. 

When spring comes around, the corms are ready to be replanted. 

For gardeners living in warmer zones, you can get away with covering the ground with a thick layer of hay or straw for the winter months. 

 

Different varieties of Gladiolus 

• Gladiolus ‘lemon drop’ – offers lemon-yellow flowers with apricot hearts. It blooms from mid to late summer. A stunning addition to any garden. 
• Gladiolus ‘Nymph’ – has creamy-white blooms with tear-shaped contrasting pink patterns. It grows up to 24 inches to 30 inches (60cm to 70cm) tall and is the perfect backdrop to smaller bushes with white and pink flowers. 
• Gladiolus ‘Little Darling’ – the darling of all gladiolus plants! It offers a show of rose-pink flowers with yellow centers. 
• Gladiolus ‘priscilla’ – is a popular choice for gardeners. It offers stunning tri-colored flowers in tones of white and rose-pink with yellow centers. This variety can grow up to 5 feet (150cm) tall. 
• Gladiolus Robinetta’ – has delightful frayed edges on flowers that are a fiery pink in color. It holds an RHS Award of Garden Merit. It grows slightly less tall, reaching heights of 2 feet (60cm). 
• Gladiolus ‘violetta’ – as the name suggests, the blooms are a stunning violet-purple color. Adding to the visual appeal are edges in a silvery-white tone. 

 

Gladiolus: Pests to look out for

Gladiolus is hardy and is not too bothered by pests and diseases. 

However, you always need to look out for possible infestations that are causing your plant to look unhappy. 

The most common pest affecting gladiolus is Thrips, known scientifically as Taeniothrips simplex. These are small, winged insects that are hard to spot.

You will see that your leaves have brown tips. Thrips can be removed by using a mild insecticidal soap. Spray onto the leaves using a light-mist spray gun. 

Another pest that enjoys gladiolus plants are leaf-eating caterpillars. You will notice masses of tiny eggs on the underside of the leaves.

When they hatch, the caterpillars will feed on the leaves and destroy your plants. Spraying with diluted neem oil is a good remedy to get rid of these pests. 

Mealybugs suck out the sap of leaves and stems, damaging the plant and causing it to eventually die. Spray with an insecticidal solution to remove them. 

 

Common problems with Gladiolus

 

Leaves have brown tips

This could be a sign of an infestation of thrips. Thrips can be removed by using a mild insecticidal soap. Spray onto the leaves using a light-mist spray gun. 

 

Bulbs don’t flower 

This could be a sign of over-fertilizing with too much nitrogen when the corms are planted. Nitrogen will burn the corms and cause them fatal harm. Ensure that your fertilizer is a balanced formula, that is not rich in nitrogen. Look for combinations of 10-10-10 or 5-10-10. 

Another reason for not flowering is the chance that your corms froze in the soil during the winter months. Most gardeners will dig up the corms and store them away for the winter. 

If you are in a warmer climate, you can get away with covering the soil with a layer or straw or hay. However, there is always a chance that a few days of icy-cold weather will freeze the corms and you will not get shoots appearing in spring. 

 

Flowers decay and the top of the plant droops

This is a sign that your plant has a disease called botrytis blight. It grows as mold-like spores and feeds off the plant. Spraying with a fungicide can help to remove the problem. 

 

My gladiolus is falling over

Some taller varieties of gladiolus do require staking to hold them upright.  Do this after planting the corms, taking care not to damage the bulbs. Guide the small shoots onto the stake as they grow. Once the plant is strong, you can remove the stakes, or choose to leave them in the ground. 

 

Gladiolus fun facts

If you enjoy trivia, read on for some fun facts. 

If you are born in the month of August, gladiolus is your birth flower. 

Gladiolus is often referred to as ‘Gladdies’ 

Vincent van Gogh painted a famous painting called Vase with Red Gladioli in 1886.  

Are you celebrating your 40th wedding anniversary? The Gladiolus flower symbolizes this amazing accomplishment. 

Scott Joplin composed a rag called “Gladiolus Rag” in 1907. 

Gladioli are associated with gladiators. They symbolize strength and integrity. 

In love, the flower symbolizes infatuation. It means ‘you pierce my heart’ as a result of its pointed shape. 

The name gladiolus comes from the Latin word Gladius, meaning Sword. 

More than 10,000 cultivars of gladiolus exist today in a range of sizes, colors, and types of blooms. You are sure to find one that you like! 

 

Frequently asked questions about gladiolus

 

Can gladiolus grow in shade?

No, shady spots are not ideal for gladiolus. It prefers full sun, which means 6 to 8 hours of direct sun per day. South-facing and west-facing gardens are best suited for gladiolus. 

 

Is gladiolus toxic? 

The bulbs of the plant are poisonous to humans and pets. The berries are also poisonous. That being said, the flower petals are edible and can be used in salads, baking, and smoothies. If in doubt, rather do not eat your gladiolus plant! 

 

Can gladiolus grow in pots?

Yes, this plant looks glorious in pots and containers. It is ideal for patios, porches, and decks where it will add a burst of color through the summer. 

 

Are gladiolus corms easy to store in winter?

You will require some time and preparation to correctly store your corms for the winter season. If you are an avid gardener, this is a worthwhile task, and you will have gladiolus that blooms year after year. See my section on Storing corms for the winter to get all the info you need on how to do this. 

 

Can I leave the bulbs in the ground? 

If you live in warmer climates, with winter temperatures of 28°F (-2°C) and above, you may get away with leaving the bulbs in the ground.  Some gardeners like to cover the area with straw or hay as protection against the cold weather. If you do have a very icy freeze, or recurring freezing weather, you may risk losing your bulbs and they won’t grow in the spring. 

 

What other plants go well with gladiolus? 

Create a beautiful garden and team up your gladiolus plants with Columbine, Black-eyed Susan, Montbretia, or Sneezeweed. Tall gladiolus plants provide a stunning backdrop for smaller, compact bushes. 

 

Do gladiolus bulbs bloom many times in summer? 

No, each corm will bloom only once. To get ongoing flowers and color, you can plant corms every 10 to 14 days apart, and then reap the rewards of ongoing flowers through the summer and into fall.