2022 will be the Year of the Gladiolus

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

      The National Garden Bureau has announced that 2022 will be the Year of the Gladiolus in the bulb category.  Gladioli (or just glads) actually grow from corms, not true bulbs, but the category has been expanded to include corms, rhizomes and other bulb-like tubers.  The name gladiolus comes from the Latin word for sword, and the leaves are certainly sword-like.  Flowers appear on tall scapes and blooms open from the bottom up.   Native to Africa and the Mediterranean area, glads have been cultivated for centuries.  The genus includes some 250 species, but most of the cultivated varieties are hybrids.

      I admit that I am not a great gladiolus fan.  My dad used to plant a row of glads across the vegetable garden, but they are rarely used in landscapes.  We had to dig the corms, dry them and store them in my grandparents’ basement for the winter.  During their growing season, we often had to stake them to keep them from falling over.  They bloom only one time, but do produce several individual flowers over a week or so.  Still, it is hard to deny that the stalks of blooms are beautiful and that they make a wonderful back-of-the-arrangement flower.  Most of the gladioli grown today are grown specifically for use as cut flowers, but they are gaining more acceptance as landscape specimens and even are being used in containers.  You may grow them in individual nursery pots and drop them into mixed containers, exchanging a spent plant for an on-coming bloomer to keep the planter going.

     Cultivated gladioli fall into five main categories.  The grandiflora hybrids are the three-to-four-foot glads that Dad (and likely your grandparents) grew.  The orchid-like flowers may be 5 to 6 inches across, and the long stalks may have 12 to 20 individual flowers.  They occur in white and every color of the rainbow except true blue, as well as bi-colors.  Some blooms are ruffled or fringed.  The draw-back is they are susceptible to falling over in windy conditions, so staking is recommended.  You may either use individual bamboo stakes or make a fence along which to grow them.  They are only hardy to zone 7, so they are usually either grown as annuals or the corms are dug and stored away to be planted again the next year.  Dwarf grandiflora hybrids resemble their larger cousins, but are only half to two-thirds the size.  This group includes the popular butterfly glads, with throat blotches in contrasting colors, and the attractive glamini glads.

     Nanus hybrids also resemble the grandifloras, but are a little smaller.  They have a more restricted color selection, offering only red, white and pink flowers and bi-colored flowers.  However, at only 18 to 24 inches tall, they are less prone to flopping and they are hardy to zone 5, so the corms may be left in the ground through our Indiana winters.  Byzantine gladioli produce around a dozen 2-inch magenta blooms on each stem.  They often naturalize in gardens in the south, but they are only hardy to zone 7.  Dalenii hybrids produce slender 2 to 3-foot stems with flowers about half the size of the grandiflora hybrids.  The blossoms also appear to have hoods instead of the fully-open flowers of other gladioli.  They are hardy to zone 6.

     Gladioli need at least 6 hours of sun each day to do well.  They also need rich soil with good drainage.  The corms of grandiflora types need to be planted 6 to 8 inches deep to develop strong stems.  Smaller varieties may be planted 4 to 6 inches deep.  All should be spaced about 6 inches apart.  In order to keep the blooms coming, succession planting is necessary, starting in mid-May and continuing until the first of July.  Flowers should appear 80 to 90 days after planting.  Regular watering is necessary, as drought-weakened plants may be attacked by thrips or spider mites.  As flowers fade, remove the spent blooms to allow the blooms above to shine.

     For the best selection of corms, shop a catalogue or website of a respected bulb merchant.  Corms will also be available in nurseries and garden centers this spring.  Buy the biggest corms you can.  Bigger corms mean larger and healthier plants.  Make 2022 the Year of the Gladiolus in your garden.