How to Grow Gladiolus: Planting, Care & Cut Flowers

Gladiolus at a glance

PlantPlant corms: 0–4 wk after last frost

SunNC State: full sun to partial shade; rich, well-drained soil; do not allow soils to dry out; protect from strong winds (NC State).

WaterMissouri: full sun; pH between 6.0 and 6.5; Mississippi State: pH 6.5–7 and about an inch of water per week.

SpacingIowa State: large corms 4 to 6 inches deep and 6 inches apart; small corms 3 inches deep; prefer corms 1½ to 2 inches in diameter (Iowa State).

Days to bloomBloom about 8-10 weeks after planting (Iowa State); Missouri 70-90+ days depending on weather and type

-3-2-1LF+1+2+3+4+5

■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.

Updated November 4, 2026

Winter dig and store: do not repeat that here — see dig and store gladiolus for curing and cool storage.

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.

Planting timing

Iowa State: “Gladiolus bulbs (corms) should be planted after the danger of frost is past.” Make successive plantings every 2 weeks; bloom about 8 to 10 weeks after planting; final planting in early July (Iowa State). UMD: tender summer-flowering bulbs including gladiolus “are planted in the spring after danger of frost” (UMD Extension). Missouri: may be planted as early as a month before average last frost, then every two weeks; last planting no later than early July; 70 to 90 or more days to bloom (Missouri Extension). Iowa/UMD lead with after frost; Missouri allows about a month before — present both.

Depth and spacing

Iowa State: large corms 4 to 6 inches deep and 6 inches apart; small corms 3 inches deep; prefer corms 1½ to 2 inches in diameter (Iowa State). Missouri: large 4–6 inches; medium 3–4; small 2–3; in-row 2–3 inches for cutting beds or at least 6 inches for show spikes. Mississippi State: 3–5 inches deep and 4–6 inches apart (Mississippi State). Sources differ by corm size — show each. Pointed end up; full sun, well drained.

Sun, soil and water

NC State: full sun to partial shade; rich, well-drained soil; do not allow soils to dry out; protect from strong winds (NC State). Missouri: full sun; pH between 6.0 and 6.5; Mississippi State: pH 6.5–7 and about an inch of water per week. Mulch 2–4 inches (Missouri). No synthetic fertilizer rates; soil test; avoid fresh manure against corms.

Care and cutting

Stake tall spikes (Missouri). Cut when the first floret shows color; leave at least two, preferably four, leaves so the new corm can mature; store cut spikes upright (Missouri; MSU). NC State notes possible contact dermatitis / pet caution for corms — state plainly, not as medical advice.