Iris

Iris germanica · Flower

Quick answer: Water: Weekly the first season, then only in drought (estimated); about 1 in per week while settling in (estimated); drought tolerant later. Light: Full sun, at least 6 hours. Soil: Well-drained, near neutral, pH 6.5–7.0 (estimated). Pets: The ASPCA lists iris as toxic to cats and dogs; the rhizome is the most harmful part. If a pet has chewed it, contact your vet.

A classic perennial with sword-shaped leaves and ruffled late-spring flowers. Bearded irises grow from thick rhizomes that sit at the soil surface. Once settled they need little water and come back for many years.

💧WaterWeekly the first season, then only in drought (estimated)

☀️LightFull sun, 6+ hours

🐾PetsToxic to pets

Care at a glance

Light: Full sun, at least 6 hours
Water: About 1 in per week while settling in (estimated); drought tolerant later
Soil: Well-drained, near neutral, pH 6.5–7.0 (estimated)
Temperature: Hardy to about -30 °F (zones 3–10)
Spacing: 12–18 in apart
Container: At least 12 in wide, 2 gallons (estimated)
Bloom: Late spring, for 2–3 weeks (estimated)
Lifespan: Perennial; divide every 3–5 years

When?

Plant rhizomes from late summer to early autumn, 6–8 weeks before the ground freezes. In mild areas this is usually August to September; in colder areas early August (estimated). Potted plants can go in during spring.

Step by step

Pick a sunny spot with good drainage; use a raised bed if your soil is heavy.
Set the rhizome shallow, with its top level with the soil or barely covered and roots spread below; do not mulch over it.
Point the leaf fans outward; three rhizomes 12 in apart soon make a full clump.
Water once after planting, then only when the soil is dry; too much water rots rhizomes.
Cut faded flower stems at the base, but leave the leaves to feed the rhizome.
Every 3–5 years after flowering, lift the clump and replant the healthy outer pieces.

Common problems

Soft, bad-smelling rhizomeBacterial rot; cut away soft parts, let it dry and improve drainage.

Streaked leaves and tunnels in the rhizomeIris borer; clear old leaves in autumn and remove damaged pieces.

Leaves but no flowersPlanted too deep, too shady or crowded; raise, move or divide.

Soft rot after heavy feedingToo much nitrogen encourages soft rot; use a low-nitrogen fertilizer and follow the label directions.

Pets

The ASPCA lists iris as toxic to cats and dogs; the rhizome is the most harmful part. If a pet has chewed it, contact your vet.

Similar plants

Daffodil Tulip Peony

Sources

This page is general guidance; no pesticide doses are given.