Gladiolus: Planting, Growing, and Storing Corms for Dramatic Summer Spikes

Gladiolus is a beloved perennial prized for its elegant, showy flowers borne on tall spikes. A staple of cutting gardens and back borders (due to their height), gladioli bloom in a rainbow of colors and reach 2–6 feet tall. They make exceptional, long-lasting cut flowers.

Planting Gladiolus Corms

• Plant in spring after frost danger passes and soil has warmed.
• Prepare the bed by loosening soil 12–15 inches deep with a fork or tiller; mix in a 2–4 inch compost layer.
• Plant corms 4 inches deep, pointed end up. Cover and firm soil.
• Space corms 3–6 inches apart; water thoroughly.
• Gladioli prefer well-drained, light soil and full sun.
• Stake tall varieties at planting time—be careful not to damage corms with stakes.
• From planting to bloom and energy storage takes about 90 days.

Seasonal Care

• Mulch 2–4 inches to retain moisture and suppress weeds.
• Water regularly if rainfall is under 1 inch/week; otherwise, moderate watering during growth.
• Deadhead faded flowers for continuous bloom. Once a stalk finishes, cut it off.
• Leave foliage intact to mature and recharge corms for next year.
• In Zones 7–8, apply hay or straw for winter protection.
• In Zone 7 and colder, dig corms before first frost (see storage below).

Pests and Diseases

• Gladiolus corm rot (Fusarium wilt)
• Gray mold
• Viruses
• Aster yellows
• Spider mites
• Thrips
• Aphids

Harvest and Winter Storage

Dig corms before first frost in cold zones.

• Use a spade to lift the entire plant, grasping the top. Avoid bruising corms. Shake off soil; discard damaged ones. Cut stalk 1 inch above corm. Save small cormels separately if desired.
• Dry corms in sun 1–2 days if weather permits. Sift excess soil; place in wooden flats/trays. Cure 2 weeks in warm (80–85°F), airy location. Remove and discard oldest bottom corms.
• Dust clean corms with fungicide ("bulb dust")—place dust and corms in a paper bag and shake vigorously.
• Store large new corms in paper boxes, open bags, cloth bags, wooden trays with screen bottoms, or onion sacks. Stack/hang for air circulation. Keep at 35–45°F in low humidity; a cool basement works well. Never allow corms to freeze.
• Replant in spring for another glorious season.
• Learn more winter storage tips for gladiolus.

Recommended Varieties

• Candyman – Deep pink flowers.
• Dream's End – Excellent back border plant with 3-ft spikes of light orange flowers with large yellow centers.
• Prins Claus – White flowers with pink splashes on petals.

Wit & Wisdom

Gladiolus is one of the August birth flowers.