Iris Pseudoacorus

Yellow Water Iris

Iris pseudacorus — commonly called yellow flag iris — is a vigorous rhizomatous perennial known for its bright golden-yellow flowers that bloom in late spring to early summer above bold, upright sword-like green foliage. This moisture-loving iris forms dense clumps and spreads readily, making it highly effective for naturalized wet areas, pond margins, and erosion control in consistently moist soils.

Type: Perennial

Mature Size:
Width: 24–36 in.
Height: 36–48 in.

USDA Zones: 4a–9b

Form: Upright, spreading clump

Light: Full sun to partial shade

Soil: Moist to wet soils; adaptable to clay and shallow standing water

Water: Medium to wet; thrives in saturated soil and shallow water

Wildlife: Attracts pollinators; deer resistant

Features & Landscape Uses: Excellent for pond edges, rain gardens, wet meadows, and naturalized water features. Strong vertical foliage remains attractive after flowering and helps stabilize wet soils.

Care: Plant in moist soil or shallow water where spreading is acceptable. Divide clumps every few years to control size. Remove spent seed pods if limiting spread is desired, as it can naturalize aggressively in favorable wet conditions.

Plant type

Perennial

Height

36-48"

Width

36-38''

Hardiness zones

4–9

Sunlight

Full Sun, Partial Shade

Flower color

Yellow

Leaf color

Green

Fall color

Green

Attracts

Butterflies, Hummingbirds

Soil

Clay, Moist well-drained, Rich

Landscape use

Accent Plant, Hedge, Mass Planting, Water Garden

Shape

Clumping, Upright

Deer resistant

Yes

Drought tolerant

No