The gladiolus flower is a popular choice for many gardeners. This type of flower is characterized by tall spikes of large blossoms in a wide variety of colors, including red, yellow, orange, white, salmon and many bi-colors. Gladioli have sword-shaped leaves and are also known as sword lilies. They are grown from corms, which are bulblike structures that need to be dug up each fall and replanted in the spring. Gladiolus flowers bloom in midsummer, but you can have a longer season of flowering by staggering planting and by choosing among early, midseason and late-blooming types.
Grandiflora hybrids are the best-known gladioli, according to Sunset.com. Spikes can reach as high as 6 feet. Modern hybrids produce very large flowers and can produce 40 blossoms on a spike. Small and miniature hybrids have been developed from grandifloras and range from 2 to 3 feet high, producing fewer than 20 flowers per spike. Grandifloras bloom about 100 days after planting and typically bloom from late spring to early autumn. They are perennials, but they are usually dug up in the fall for replanting in the spring.
Gladioli in the nanus group bloom in early summer. They are winter-hardy gladioli and can handle freezing temperatures, blooming year after year without replanting. These gladiolus flowers are shorter than other types of gladioli, usually ranging from 1 to 2 feet tall. They mingle well in flower gardens with other perennials. Nanus gladioli are often used for corsages and flower arrangements.
Winter blooming species of gladioli tend to be smaller plants that produce only one or two leaves before flowering, according to the University of Arizona. They are native to South Africa, and more than 100 different winter blooming species exist. These gladiolus flowers often have strong fragrances.
Primulines are a small variety of gladiolus that flowers in the summer and typically produces only one thin spike. Gladiolus flowers have been frequently hybridized, and new varieties are continually being developed. Large, showy gladioli are often displayed in flower shows and used as cut flowers. Petals can be plain, ruffled, semiruffled or frilled. Miniature varieties are suited as borders or in smaller arrangements of cut flowers. According to the University of Missouri Extension, gladioli are categorized based on size of the bloom. They are also coded according to color and whether they have conspicuous markings.