Iris Growing Guide

Iris

Crop Rotation Group

Miscellaneous 

Soil

Rich, fertile soil with excellent drainage.

Position

Full sun.

Frost tolerant

Excellent. Most popular garden irises are hardy to -25F (-32C).

Feeding

Topdress with rich compost in mid spring, after new growth appears. Fertilize with a liquid fertilizer in midsummer.

Companions

Allium, Daylily and Salpiglossis. Showy iris blossoms look especially beautiful when they rise above the foliage of low-growing flowers with fine-textured foliage such as lobelia or sweet alyssum.

Spacing

Single Plants: 11" (30cm) each way (minimum)
Rows: 7" (20cm) with 1' 1" (35cm) row gap (minimum)

Sow and Plant

Set out plump rhizomes with a fan of foliage attached in spring, just as new growth appears, or in early fall. Plant shallow, so that the rhizomes are barely covered with soil. Allow 12in (30cm) between large-flowered bearded irises. Siberian iris roots should be planted 6in (15cm) apart.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Iris may not bloom for a year after they are moved. Choose early and late-blooming varieties to extend the iris season. Several newer varieties will re-bloom in the fall with good care.

Harvesting

Cut irises for arrangements as soon as the buds show good color; they will continue to open indoors. As the flowers fade in the garden, trim them off with scissors or pruning shears.

Troubleshooting

Several insects damage iris roots. When digging and replanting an old plot, cut away pieces of injured root. Siberian iris have few pest problems, and are seldom eaten by deer.

Planting and Harvesting Calendar

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Pests which Affect Iris