Looking for tips on how to get your gladiolus to bloom big this summer with stunning flowers that soar high into the air?
Gladiolus, or “Glads”, as many gardeners call them, are classic flowering perennials that resemble long swords, which often gives the plants the nickname “sword lily” as well. But whatever you call them, their flowers can be nothing short of incredible!
What really makes a gladiolus plant stand out is its gorgeous towering flower spikes. Covered in multiple blooms in a huge array of red, pink, orange, yellow, white, purple, and variegated colors, these flower spikes are simply an explosion of color and texture.
The flower is beloved for a long list of reasons. Not only do gladiolus make for stunning displays in your garden and flowerbeds, they also make amazing cut flowers as well. In fact, you often can find gladioli grouped together in vase displays as well as paired with other floral arrangements.
But how can you ensure that your gladiolus plants produce these incredible displays of blooms? When glads struggle to bloom – it usually comes down to one of three issues – not having the right soil, not getting planted at the right time, and not getting the right amount of water and fertilizer. Here is a look at each – and how to give your gladiolus just what they need to flower big!
3 Secrets To Get Your Gladiolus To Bloom Big This Summer
1. Giving Gladiolus The Right Soil For Big Blooms
Gladiolus plants prefer soil that is well-draining and full of organic matter. And if your gladiolus struggle to bloom, it may very well be they are in too hard of a soil – or a soil with the wrong pH.
The soil should be slightly acidic to neutral with a pH of around 6.0 to 6.5. However, the most important aspect of the soil is that it needs to drain well. Gladiolus corms are prone to rot if the soil is constantly damp.
Amend heavier soils such as clay that are prone to compaction by adding a few cups of sand before planting. And no matter what your soil type is, adding a cup or two of compost into the planting hole as well will do wonders for big summer blooms.
Compost is a huge key to giving the corms exactly what they need to sprout and grow fast. That same compost also helps the plant absorb the water and nutrients it needs to set blooms.
2. Planting Gladiolus At The Right Time
Another big issue for gladiolus is going in the ground at the wrong time. You can plant gladioli corms about two weeks before your last spring frost date. Ensure that the soil is at least 55-60º Fahrenheit before planting. Cold soil can spell big problems for later blooming ability.
You can plant gladiolus bulbs every couple of weeks until early summer to extend your blooming season. Most will take between 60 to 90 days to grow before blooming. Affiliate Link: Mixed Gladiolus Flower Bulbs – 50 Bulbs Assorted Colors
Choose a location that receives full sun for at least 6 to 8 hours a day. Gladiolus flowers will still bloom in partial shade, but you will get better results in full sun.
Last but not least, select gladioli corms that are at least an inch or more in diameter for the best success with growing and blooming. Dig a hole that is about an inch wider than your corm and at least 6 inches deep. Add a couple of inches of compost in the bottom of each hole. Affiliate Product Link: Black Kow Nitrogen Phosphate Composted Cow Manure Fertilizer)
Place a corm into the hole with the pointy end facing up and the flatter ends down into the soil. Backfill with soil and water well. Space additional corms about 6 to 8 inches apart.
3. Giving Your Gladiolus The Right Amount Of Water & Fertilizer For Big Blooms
Watering is key as well. After your initial soaking, water your gladiolus plants about once a week. Gladiolus corms do not handle overly wet soil well and can easily rot, so avoid overwatering.
Aim for giving gladiolus plants around one inch of water each week. Take rainfall into consideration to this. If experiencing extremely hot spells, you may need to increase watering frequency.
To help retain moisture while also preventing weeds, add a few inches of natural mulch around the gladiolus plants. Straw, shredded leaves, and grass clipping all make for excellent mulch.
Along with the compost you initially added to the soil, add an all-natural liquid fertilizer after the plants are around a foot tall. Fertilize once more when the gladiolus plant begins to flower. You can also use compost tea to help boost the nutrient value of the soil around your gladioli. See How To Make and Use Compost Tea.
With taller varieties, you need to add some sort of support for the tall stems. Strong winds and harsh rains can bend and deform the flowers if they don’t have adequate support.
You can use anything from bamboo shoots, plant cages, or fence lines. Add your supports right after planting the corms, being sure not to damage them during insertion. Once the flower stalk starts to grow, loosely tie the stem to your support. You will need to adjust the ties as the gladiolus grows.
Pruning & Overwintering
Gladiolus flowers do not require pruning since the flowers only grow along the main stem. You may wish to pinch off the spent blooms, but it is not necessary for them to grow well.
You need to deadhead the spent stem after the blooms have all died off. This helps to prevent the gladiolus from going to seed. Unless you are planning on storing the corms for next year, use a sharp pair of garden shears and cut the main stem off at the soil line.
Gladiolus corms can be left in the ground over winter in growing zones 7 and above. These corms will come back next year. Simply cut back the spent plant to the ground. During late fall, add several inches of mulch for better winter protection.
Gladioli plants are typically treated as annual plants in colder growing zones. However, you can overwinter them by digging up the corms prior to your first frost. Dry corms in a dark location for about three weeks. After they have dried, remove any excess soil, the roots, and any new baby cormlets that have grown out from the main corm.
Store dried corms in a dry, dark, and cool location that has plenty of airflow. Paper bags, onion sacks, or any other cloth bag that allows for air movement works well. Make sure not to allow the corms to freeze.
Any baby corms that are over half an inch wide can be kept to use as new corms in the following year. Just keep in mind that these smaller corms may not bloom in their first year.
Cut Flowers
Gladiolus flowering stalks make for excellent cut arrangements. Cut flowers early in the morning or at night. Choose a stem that has only a few of its bottom blooms open. The rest of the buds should be closed.
Use a pair of gardening shears and cut the stem diagonally. Immediately place it in a bucket or pail of room temperature water. Make sure to leave a few of the gladiolus leaves on the plant if you plan on overwintering corms for next year’s growth.
Remove any leaves that will be submerged in water within your vase or container. Change the container’s water often and add a cut flower food if preferred.
Keep cut flowers out of direct sunlight and drafty locations. You can either remove or leave spent blooms alone. Gladiolus flowers usually last around a week but can last up to two weeks under ideal conditions.
Not only can growing gladiolus plants make for a striking display in your garden and flowerbeds, but using them as cut flowers is also a great way to brighten up your home. Here’s to enjoying the beauty and color of growing huge gladiolus blooms this year!
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