Updated: Jul 31
Gladiolus is a beautiful half-hardy flower that grows well in the winter season in the plains of India. The name derives from the Latin word gladius, meaning “sword”. The spiked petals give it a distinct shape and the flowers come in a wide variety of vibrant colours, making for a spectacular view in any garden or yard. This crop is best suited for sowing in the beds. While they don’t bloom continuously throughout the season, gardeners can plant them on a staggered schedule to ensure that their garden is always bursting with the great colours of this low-maintenance flower.
How To Plant Gladiolus
Light: Gladiolus grow and flower best in full sun. Gladiolus corms will flower in part shade, but the colours will not be as vivid as when planted in full sun, and the plant won't grow quite as well.
Soil: Gladiolus like well-drained, sandy loam soil. The corms will rot if the soil is too heavy and remains wet. If you have clay soil, grow in flatbeds and loosen the soil to 12 inches deep before planting. Fertilize the soil well with Farm Yard Manure (FYM) before planting.
Spacing: Space gladiolus corms 6 to 8 inches apart in the garden and plant corms 2 to 4 inches deep depending upon the size of the corm (plant bigger corms deeper).
Planting: Plant gladiolus corms in autumn. To enjoy flowers all winter, plant your Glads every one week starting September until early October. This will stagger the plantings and flowering times. You can also extend the flower season by growing early, mid and late-season Gladiolus varieties.
How To Care For Gladiolus Throughout the Season
Growth Habit: Gladiolus have narrow, sword-like leaves and tall flower stalks. The flower stalks can grow 2 to 3 feet tall while only spreading 1 foot wide.
Staking: Gladiolus flower stalks need to be staked, caged or supported so they don't flop over, or become deformed and curved due to summer storms. Soon after planting, push flower stakes into the ground or add supports around the corm. Do this early so as not to damage the flower. As soon as the flower stalk forms, tie it loosely to a stake with a soft material, or use flower rings to support it. Remove the stakes after the flower is harvested or fades.
Planting gladiolus in groups in the garden or next to tall bushy plants is another way to keep them growing upright without producing crooked flower stalks.
Watering: Keep gladiolus plants well watered with at least 1 inch of water a week. This amount may have to increase during periods of drought or if you're growing in raised beds.
Fertilising: Add compost (FYM) to the soil before planting gladiolus. Add an organic, water-soluble fertiliser when the plants are 10 inches tall, and again when the flowers start to show colour. Some kind of Nitrogenous fertilizer is required when plants are about one foot tall.
Trimming & Pruning: Gladiolus are either grown as a cut flower for indoor arrangements, or as an annual flower in the garden. They don't require trimming or pruning.
The flower stalk is harvested in the morning for flower arrangements when the lower 3 blossoms on the stalks just begin to open. Leave at least 4 leaves on the plant to rejuvenate the corms if you plan on saving them for next year.
In the garden, deadhead the flower stalk after the flowers fade. This will also prevent the flowers from setting seed and self-sowing throughout your beds. Although these seedlings will eventually get large enough to flower, it will take years and the seedlings can become weedy. However, the best method is to preserve corms after the season and store indoors in a dry cool place for sowing again next year.
Mulching: To preserve soil moisture, mulch plants once they emerge from the soil with a 2 to 3-inch thick layer of straw or bark mulch. Mulching can be done with dark polythene sheet. Gladiolus don't compete well with weeds. If the area where you'd like to plant is weedy, weed before applying the mulch. The mulch should help with weed control as well.
Pests/ Disease: The best way to avoid insects and disease problems on gladiolus is to buy healthy corms that are not soft or crumbly. Discard any damaged or rotting corms that you are storing. If you notice stunted, gnarly growth on one gladiolus plant during the growing season, remove and destroy the plant and corm, as it probably has a virus.
The biggest pest of gladiolus is a small insect called thrips. Thrips feed on the flowers and leaves causing characteristic streaking and discolouring on the flowers. Thrips survive on saved corms. You can discard corms after one year and buy new corms each year to avoid thrips, or you can treat your corms before storing, by dipping them in boiling water for 2 minutes to kill the thrips. Dry before storing. During the growing season, spray your gladiolus plants at first signs of damage with Neem oil or insecticidal soap to kill them.
Watch for flowers that have been affected by any pests or browning and remove any diseased plants to keep the disease from spreading. At the first frost, dig up the bulbs and allow them to dry for a few weeks before putting them in a cool, dry place for storage. Keep them in plastic mesh bags in a well-ventilated area that stays around 20-25 degrees Centigrade and then replant them in the spring.