Irises should be planted in a sunny location in prepared soil during the months of July, August and September. Optimal planting times vary by location, but irises should be planted at least four to six weeks before the season's anticipated hard frost date.
- Choose a site
Irises thrive when they receive between six to eight hours of sunshine per day. Although some afternoon shade may be desirable in excessively hot locations, too much shade has a negative impact on flowering.
- Prepare the soil
Irises perform best in well-drained, arable and slightly acidic soils. Soil testing kits can provide pH levels, and amendments can be added accordingly. The addition of organic material improves drainage.
- Plant the rhizomes
Create a shallow planting hole that allows the tops of the rhizomes to remain visible. Place the rhizome in the planting hole, spread the roots out, and barely cover it with soil. In desert climates, they may be covered with up to 1 inch of soil, where water is used to stick them into place.