Gladiolus, commonly called glads, are not annuals, but perennial flowering plants that grow from corms in home landscapes. However, seasonal harvesting and storage of the corms is necessary in order to grow glads as a perennial flower. If left in the ground the corm will die with cold winter temperatures in most planting locations in the United States. Gladiolus is easy to grow in home landscapes with minimal care and seasonal maintenance.
Gladiolus is a large perennial flowering plant that grows between 2 to 4 feet tall. The plant has numerous long, slender leaves and develops a tall flowering stalk with dense clusters of brightly colored flowers. Gladiolus blooms have a wide range of colors including purple, pink, red, orange, white and yellow as well as many bicolored varieties.
Glads grow best when planted in full sunlight. Choose areas on your property with rich, well-drained soils and good air circulation. A sunny location with a high level of nutrients available is important for growing stiff flower stalks that do not droop, as well as for the corm to store energy needed for the following season's growth.
Choose high-quality corms that have a tall, plump shape. Corms that are taller than they are wide will produce more vigorous plants in your landscape, according to horticulturalists at North Dakota State University. Till the soil thoroughly to a depth of 12 inches at the planting location to loosed up the soil and facilitate healthy root development. Plant corms with the pointed side facing toward the soil surface to a depth four times their diameter. Allow 6 to 8 inches between each plant. .
Place a thin layer of organic mulch around the base of the plants once they sprout in your landscape. Mulch helps conserve soil moisture and prevent weeds from competing with the flowers for nutrients. Remove any weeds as soon as you see them and water the plants as needed when the soil dries out -- at least 1 inch of water weekly is adequate.
Dig up the gladiolus corms when the foliage dies back after the first frost. Cut the faded foliage off just above the corm and remove any soil attached to the corm. Store the corms in a warm, dry place for three weeks to cure them before storage. Several new corms will have developed around the original corm you planted. Break these clusters up by hand and place all the cured corms in a cool dry location with temperatures between 35 and 45 degrees Fahrenheit over winter. Replant the corms in spring after the risk of frost has passed.
- North Dakota State University Extension; Giddy Over Gladiolus; Ronald C. Smith; August 1993
- University of Minnesota Extension Yard and Garden Brief; Growing Gladiolus; July 2001
- University of Missouri Extension; Summer Flowering Bulbs: Gladiolus; David Trinklein; October 2005
- Washington State University Spokane Extension; Gladiolus; LaVerle McCandless; January 2005
- University of California Statewide Integrated Pest Management Program: Gladiolus
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