When to Plant Bearded Iris in New Hampshire

Growing Bearded Iris in New Hampshire: Complete Guide

Bearded Iris (Iris germanica) is fall-planted — it goes in the ground a few weeks before the first fall frost and overwinters for blooms the following spring. Depending on your zone, New Hampshire gardeners plant between July 21, 2026 (Zone 4b) and July 16, 2027 (Zone 4a).

Because New Hampshire stretches across 6 USDA hardiness zones (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 240 days to maturity, Bearded Iris fits comfortably within New Hampshire's growing season in most zones. In the warmest parts of the state, a second planting later in the season may be possible.

Bearded Iris requires full sun (6+ hours) and low; avoid wet soil moisture. In the Northeast, cool summers and moderate humidity can slow warm-season crops, so choose a sheltered, south-facing spot to maximise heat.

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 New Hampshire.