When to Plant Gladiolus in Montana

Growing Gladiolus in Montana: Complete Guide

Gladiolus (Gladiolus × hortulanus) is planted as dormant bulbs. Depending on your zone, the right window in Montana falls between April 22, 2027 (Zone 6b) and May 27, 2027 (Zone 3b).

Because Montana stretches across 7 USDA hardiness zones (3b, 4a, 4b, 5a, 5b, 6a, 6b), planting windows can shift by as much as six to eight weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.

With 80 days to maturity, Gladiolus fits comfortably within Montana's growing season in most zones. In the warmest parts of the state, a second planting later in the season may be possible.

Gladiolus requires full sun (6+ hours) and regular (1 inch/week) moisture. Mountain-state gardens contend with short seasons and intense UV at elevation — cold nights can persist well into June at higher altitudes.

For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Montana.