How to Grow Gladiolus Plants in your Garden

Gardener's HQ Guide to Growing Gladioli, Corn Lily, and Sword Lilies

Members of the Gladiolus genus are half hardy or hardy bulbs that range in height from 30 cm to 1.5 Metres (1 to 5 feet).

They bear attractive flowers along upright stems and bloom from summer through to the start of autumn.

Some common names for Gladiolus plants include Gladioli, Corn Flag, and Sword Lily.

Gladiolus Callianthus
Gladiolus Callianthus - Peacock Orchid by pizzodisevo

Gladiolus by AvidlyAbide.

How to Grow Gladiolus

Gladiolus Growing Guide and Facts

Common Names: Gladioli, Sword Lily, Marsh Afrikaner, Corn flag, Corn Lily, Long Tubed Painted Lady.
Life Cycle: Hardy bulb. Half hardy bulb
Height: 18 to 60 inches (45 to 150 cm).
Native: Africa, Mediterranean, Asia.
Growing Region: Zones 2 to 10.
Flowers: Summer until early autumn.
Flower Details: Most colours. Fragrant. One-sided spikes. Funnel-shaped.
Small. Clustered. Fragrant. Daisy-like ray and disc florets. Bell-shaped. Tubular. Trumpets. Inconspicuous pale green; plants are grown for their attractive silvery or bronze spearheads.
Foliage: Herbaceous. Sword-like. Erect.
Grow Outside: Usually grown from bulbs as seed grown plants will not bear flowers for about five years.
Corm: 4 to 6 inches (10 to 15 cm); deeper in sandy soils than clay soils. Once a fortnight from a few weeks after the last frost for two months. Spacing 4 to 6 inches (10 to 15 cm).
Sow Inside: Seeds: 1/8 inch (6 mm). Late in winter. Germination time: 3 to 6 weeks. Temperature: 70°F (21°C). Transplant outdoors a few weeks after last frost.
Requirements and care: Full sunlight. Good drainage. Soil pH 6.0 to 7.0. Regular watering. Provide a light feeds at budding, blooming and once flowering has completed. Provide support if needed. Bring bulbs indoors over the winter in colder areas and store in a frost free, dark and cool place. Divide every few years to maintain vigour. Propagate: from cormels.
Miscellaneous: Considered a weed in some cultivated areas.

How to Grow Gladioli

It is easiest to grow Gladioli from bulbs; though members of the Gladiolus genus can be grown from seed it is quite difficult and they will take at least three years to germinate.

The Gladioli bulbs should be buried at a depth of 10 to 15 cm (4 to 6 inches) and a spacing of 10cm (4 inches; small Gladiolus species) to 15 cm (6 inches; larger Gladiolus varieties).

Plant the Gladioli corms every two weeks throughout the winter; this will produce a prolonged bloom of your Gladiolas.

Ideally Gladioli will grow in a sunny area that has a rich soil that is slightly acidic to neutral in pH.

If you do want to grow from seed, then sow them indoors first. Sow Gladioli seeds at a depth of 3 mm (1/8th inch); it should take them about three to six weeks to germinate at a temperature of 20 to 24 degrees centigrade (68-75°F). Transplant young Gladioli seedlings about three weeks after the last chance of a frost.

Gladioli in bloom
Gladioli in bloom by born1945.

Caring for Gladioli

It is fairly easy to look after genus members such as Sword lily and Gladioli. They should be watered regularly.

Stake taller Gladiolus varieties; especially if you have had to plant them shallowly.

Gladioli should be fertilised three times a year; upon bud development; upon blooming and following blooming.

If you require more plants then propagate by planting the cormells that older corms produce.

I hope that you enjoyed this guide on how to grow Gladiolus plants. Updated September 2020.