Culture
Grow in average, medium moisture, well-drained soils in full sun. Tolerates some part afternoon shade. Prefers light, well-drained, organically rich soils. Site in a sheltered location protected from strong winds. Corms are best planted in fall. Plant corms 4” deep and 4-6” apart. Best planted in groups of at least 5-7. May be easily grown in the St. Louis area without lifting the corms in fall. Mulch in winter with hay/straw or evergreen boughs. Will naturalize in the garden over time.
Noteworthy Characteristics
Gladiolus is a genus of about 180 species of corm-bearing plants from mainly South Africa but also found in the Mediterranean, Arabian Peninsula, northwestern Africa and eastern Africa. The wide range of hybrids produce some of the showiest of summer garden flowers. They are also a mainstay in the florist trade. Gladiolus produce sword-shaped, medium green leaves in upright fans and funnel-shaped flowers on slender scapes from summer into fall. There is an extensive range of flower colors available, including shades of white, cream, yellow, orange, red, pink, lavender, purple and green. Most of the gladiolus sold today are hybrids which are commonly designated as Gladiolus × hortulanus. At least eight different species have been utilized in breeding modern gladiolus, and the parentage of most cultivars is not known. Plants can be classified by their overall size as well as the size and shape of the blooms. Modern hybrids can be divided into three main groups:
a. Grandiflora hybrids. Funnel-shaped, large-flowered gladiolas with 4-6” wide blooms on 3-6’ tall scapes. Up to 30 flowers per spike. Extensive range of flower colors. Considered the most difficult group to grow in typical garden settings.
b. Nanus hybrids. Miniature hybrids with small flaring blooms reaching up to 3” wide on 1.5’ tall scapes.
c. Primulinus hybrids. Hooded-type flowers held loosely on 2-4’ tall scapes. Butterfly hybrids, often included as a subgroup of the Primulinus hybrids, feature flowers with ruffled petals and contrasting throat blotches and other markings on 2-3’ tall scapes.
Genus name comes from the Latin word for a small sword in allusion to the shape of the leaves. The plants are also sometimes called sword-lilies but people generally use the Latin plural gladioli.
Winter hardy gladioli are similar to the popular Grandiflora hybrids, except they grow much shorter, the flowering stalks are more slender, the individual flowers are smaller and the corms do not need to be lifted in fall in the St. Louis climate. The hardy mixes sold by many nurseries feature white, pink, red, orange and bi-color flowers on stalks typically rising to 20” tall. Flowers bloom in late spring to early summer. Sword shaped green leaves.
Problems
Susceptible to botrytis, crown rot, rust, wilt and mosaic virus. Watch for aphids, mealy bugs, spider mites and thrips. If thrips were a problem during the growing season, consider treating corms with an insecticide prior to storage.
Uses
Beds, borders. Container plant for decks and patios.