Gladiolus
Gladiolus
Gladiolus blooms from July through August.
Mature size, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not.
Growing Gladiolus
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 7–10. Expect it to reach about 3.9 ft tall and 8 in wide at maturity, in roughly 1 year.
When to plant Gladiolus
Gladiolus is tender: plant it out after the last frost, once the soil has warmed. In the middle of its hardy zones 7 to 10 range that means March or April; where spring comes later, it goes out later. Expect flowers from July to August.
Month-by-month timing for your zone is on the planting calendar: for the middle of its range, start with zone 8 in March.
Comes in 11 varieties across 5 colors
Same plant, same care - pick the color you are growing.
Good to know about Gladiolus
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Toxic to dogs, cats and horses; the toxins concentrate in the corm. Eating it usually causes drooling, vomiting, lethargy and diarrhea. per ASPCA
Worth knowing
Each corm blooms just once and the spike is short-lived, so plant corms in stages about a week apart to keep flowers coming all summer. per Clemson
Leave corms in, or lift?
Zones 8 to 10 can leave corms in the ground; zone 7 is borderline, so mulch or lift; zone 6 and colder must dig and store them. per NC State
Tall spikes flop; stake them
The tall, one-sided flower spikes get top-heavy and topple in wind or rain. Stake them, hill soil around the base, or plant corms 4 to 6 in deep. per Clemson and NC State
Sanitize corms at digging
Gladiolus thrips and the corm rot fungi both overwinter on stored corms. One digging-time routine (discard infested or lesioned corms, destroy old debris, cure dry, store cool) beats both. per NC State and University of Illinois
About 70 to 90 days
Corms take 70 to 90 days from planting to flower, so bloom timing follows your planting date. A spring planting flowers mid to late summer, later plantings into fall. per NC State and Clemson
Flowers open bottom to top
The tall, one-sided spike opens its funnel-shaped flowers in sequence from the bottom upward, so the lowest blooms fade while fresh buds are still opening at the tip. per NC State
What pairs well with Gladiolus
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Candytuft
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; lower at 10 in, for the front of the border; evergreen, so the bed keeps its shape through winter.
Sea Thrift
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; lower at 8 in, for the front of the border; evergreen, so the bed keeps its shape through winter; they only overlap in zones 7 to 8.
Autumn Crocus
Shares full sun and moderate water; blooms in early fall as this one finishes; low at 6 in, to carpet the ground beneath.
False Indigo
Shares full sun and low to moderate water; blooms in late spring, before this one opens; its seed heads stand through winter, for structure and the birds.
Pansy
Takes full sun to part sun and moderate water; blooms in early spring, before this one opens; lower at 8 in, for the front of the border.
Sweet Alyssum
Shares full sun and moderate water; overlaps, then carries the display into mid fall; low at 5 in, to carpet the ground beneath; its white flowers settle the pink.
Bacopa
Takes full sun to part sun and moderate water; overlaps, then carries the display into mid fall; low at 6 in, to carpet the ground beneath; its white flowers settle the pink.
Blue Oat Grass
Shares full sun and low to moderate water; opens in early summer and overlaps into this one's season; evergreen, so the bed keeps its shape through winter; lower at 2.3 ft, for the front of the border.
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