When Does Gladiolus Sprout?

When Does Gladiolus Sprout?

The flower spikes of gladiolus hybrids mixed amid the unusual blossoms of species gladiolus supply a constantly changing landscape during the seasons at a mild-winter Mediterranean climate. Hardy at U.S. Department of Agriculture plant hardiness zones 5 through 10, based on the variety, gladiolus (Gladiolus ssp.) Are indigenous to Africa, the Middle East and Europe. The familiar flowers of highly hybridized varieties are often seen in cottage gardens and florist shops. The less commonly seen South African varieties are planted in late autumn, creating delicate, vibrant blooms in late winter and early spring.


Gladiolus grow from a corm, which is really a thick, bulblike stem. Generally, corms are planted between 3 and 5 inches deep, or four times the height of the corm. Stakes are often placed beside the corms when they are implanted, providing a sturdy support for tall flower spikes. The corms develop a root system before sending green shoots, usually in three to five weeks, based on temperature and humidity conditions. Even though gladiolus are not fussy about soil type, so long as it drains well, they prefer a pH level of 6.7 to 7.


While most gladiolus are increased from corms, many gardeners hand-pollinate the blooms to develop new hybrids. Once the seed pods ripen, the seeds have been harvested and implanted either immediately or the following spring. The seeds are put in seed trays, covered with 3/8-inch moist sand or vermiculite, and kept warm. Gladiolus seeds germinate in 10 to 14 days. The newest gladiolus plants develop corms from the first season and generally bloom in their second season. Suitable specimens must be dug up at the end of the season and the corms split in order to propagate the hybrid.

Species Gladiolus

Planting many different species gladiolus corms every two weeks ensures a very long blooming season at the lawn. Start with the early-blooming varieties like Gladiolus miniatus, planting the corms as soon as the likelihood of frost has passed. Insert mid- and also late-season varieties like G. dalenii and the peacock lily (G. muriale) as summer progresses, again staggering the plantings by two weeks. Finally, at the autumn, include the winter-blooming varieties, like G. caeruleus, G. trichonemifolius and G. watsonius, to get a year-round display of the unusual species’ blooms.

Gladiolus Hybrids

The tall spikes of gladiolus flowers found at florists and in many gardens across the United States are hybrids, bred from summer-growing varieties like Gladiolus dalenii and G. papilio. These warm-weather gladiolus hybrids are available at local retailers and online, in many different shades and sizes. The corms are well-developed and mature, ready for planting. Sprouting in three to five weeks, they produce blossoms the first year. In mild winter climates, they may be left at the ground during the winter months, however, in severe areas they are generally lifted and the new corms are divided for planting in the spring.

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