When to plant iris
Plant iris in fall, 6–10 weeks before the first fall frost. That works out to zone 5b (late July to late August), zone 7a (mid August to mid September) and zone 9a (mid September to mid October).
Iris planting dates by zone
| Zone | Plant |
|---|---|
| 4a | Jul 18 – Aug 15 |
| 4b | Jul 21 – Aug 18 |
| 5a | Jul 23 – Aug 20 |
| 5b | Jul 30 – Aug 27 |
| 6a | Aug 6 – Sep 3 |
| 6b | Aug 10 – Sep 7 |
| 7a | Aug 16 – Sep 13 |
| 7b | Aug 23 – Sep 20 |
| 8a | Aug 29 – Sep 26 |
| 8b | Sep 6 – Oct 4 |
| 9a | Sep 17 – Oct 15 |
| 9b | Oct 1 – Oct 29 |
How to plant iris
| Plant as | rhizomes |
|---|---|
| Depth | Rhizome top at soil level |
| Spacing | 12–24 in |
| Light | Full sun |
| Time to bloom | 1–2 years |
| Hardiness | Perennial in zones 3–9 |
Plant and divide bearded iris in late summer so roots establish before winter.
Leave the top of the rhizome exposed to the sun.
Good drainage prevents rhizome rot.
When to expect flowers from iris
Bearded iris bloom in late spring; divide clumps every 3–5 years in late summer.
Exact dates for your town: planting calendar · frost dates by state.
More flowers to plant
Begonias · Coleus · Marigolds · Zinnias · Sunflowers · Cosmos · Mums · Lantana