When to Plant Bearded Iris in District of Columbia

Plant Bulbs (Fall)

Sunday, September 6, 2026

Based on Washington · Zone 8a

Last frost: Saturday, March 20, 2027

State

District of Columbia

USDA Zones

7a, 7b, 8a

Avg Last Frost

Saturday, March 20, 2027

Cities Covered

District of Columbia Planting Schedule by Zone

District of Columbia spans 3 zones — find yours below for the most accurate dates.

Zone	Last Frost	Plant (Fall)	Example Cities
7a	Saturday, April 10, 2027	Thursday, August 20, 2026	Washington
7b	Monday, April 5, 2027	Sunday, August 30, 2026	Washington
8a	Saturday, March 20, 2027	Sunday, September 6, 2026	Washington, Washington Navy Yard

Dates based on average last frost. Check your local forecast before planting.

About Bearded Iris

Scientific Name Iris germanica

Days to Maturity 240 days

Plant Type Rhizome (late-summer planted)

Sun Full Sun (6+ hours)

Water Low; avoid wet soil

Spacing 16" apart

Growing Bearded Iris in District of Columbia: 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, District of Columbia gardeners plant between August 20, 2026 (Zone 7a) and September 6, 2026 (Zone 8a).

Because District of Columbia stretches across 3 USDA hardiness zones (7a, 7b, 8a), planting windows can shift by as much as two to four 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 District of Columbia'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. Check your local forecast for humidity and heat advisories that may affect timing and pest pressure.

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 District of Columbia.

Frequently Asked Questions

When should I plant Bearded Iris in District of Columbia?

In District of Columbia, plant Bearded Iris bulbs in fall, around Sunday, September 6, 2026, so roots establish before the ground freezes. District of Columbia spans zones 7a–8a, so exact timing shifts with your zone's first fall frost.

What is the last frost date in District of Columbia?

District of Columbia spans 3 USDA zones (7a, 7b, 8a), so last frost dates vary by region. Washington (7a) sees frost until around Saturday, April 10, 2027, while Washington, Washington Navy Yard (8a) is frost-free much earlier.

How long does Bearded Iris take to grow in District of Columbia?

Bearded Iris takes about 240 days from planting to bloom. Fall planting lets roots establish over winter for spring blooms.

What USDA zones does District of Columbia cover for Bearded Iris?

District of Columbia includes zones 7a, 7b, 8a. Bearded Iris grows well across all of these zones with adjusted timing — use the zone table above to find the right dates for your part of the state.

When to Plant Bearded Iris by City in District of Columbia

Dates are based on each city's USDA zone and average last frost.

City	Zone	Last Frost	Plant (Fall)
Washington	8a	Saturday, March 20, 2027	Sunday, September 6, 2026
Washington Navy Yard	8a	Saturday, March 20, 2027	Sunday, September 6, 2026

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