Texas Cooperative Extension,
Texas A&M University, College Station, Texas

March 2007

Gladiolus in the Garden

by Dr. William C. Welch

Gladiolus are grown for their showy spikes of flowers which come in many colors. There are large-flowering types as well as small.

Glads may be used as background plants in the garden, or in rows, or as cut flowers for the home. If care is given to a planting schedule, flowers can be available from early summer until frost. To achieve this, the corms are planted at various times, usually at 2- or 3-week intervals, from as early as mid-February until the last of April. Set the corms 4 to 5 inches deep and 5 to 6 inches apart in groups or rows.

Gladiolus prefer well-prepared garden soils with good drainage. As soon as plants are 6 to 8 inches tall, apply fertilizer, such as 13-13-13, at the rate of 3 to 4 pounds per 100 square feet. Organic fertilizer sources, such as cottonseed meal, also work well. Water thoroughly when soil appears dry, and stake if necessary.

To save gladiolus corms for next year, dig the corms after the foliage has dried in late summer or fall. Remove the soil and snap off the dead tops. The old or original corm may be removed and discarded at this time. Spread the corms out on the garage or storage-room floor and allow to dry for 3 to 4 days. Place the corms in boxes with dry peat moss or sawdust. If large numbers are involved, make some boxes that are 3 to 4 inches deep with bottoms made of hardware cloth. Store in a dry, cool place at a temperature of 45 to 50 degrees F. Check them periodically during the winter for signs of rotting or rodent damage, and discard those affected.

At least two species of gladiolus are considered heirloom plants in our area and may be left in the ground and grown as perennials. Gladiolus byzantinus, sometimes known as cornflags, mark many old home sites and cemetery plots in Texas and the South. Their magenta and rarely-white flower spikes are smaller than the hybrids usually available in florists and nurseries.

Another interesting gladiolus is Gladiolus natalensis, sometimes known as the parrot gladiolus. Flowers of this species, which is native to Africa, are larger than those of G. byzantinus, and are a brilliant combination of yellowish green and red.

Both of these gladiolus may be grown as perennials, and usually increase in numbers each year. They are commercially available, however, only from specialty bulb sources.

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