Iris pseudacorus: Yellow Flag Iris for Wetlands and Water Gardens

Iris pseudacorus (yellow flag) is a vigorous Laevigata iris with ribbed, sword-shaped gray-green leaves, growing 3–4 feet high. Over 60 cultivars exist, including 'Beuron' (evenly yellow), 'Ecru' (off-white), 'Fresh Cream' (pale yellow with red-violet signals), variegated 'Variegata', 'Donau' (bright yellow with brown signal), and nearly sterile 'Holden Clough' (deep yellow with reddish purple veining).

Noteworthy Characteristics

Extremely adaptable. Self-seeds freely along streambanks and pond edges. Flourishes in both shallow and deeper waters.

Care

Grow in full sun to part shade and most any moist soil. Cut flower spikes at end of growing season to prevent excessive self-seeding. Sterile cultivars exist.

Propagation

Lift and divide clumps, or separate bulb offsets, and plant immediately in early autumn.

Problems

Iris borer, verbena bud moth, whiteflies, iris weevil, thrips, slugs and snails, aphids, and nematodes.

Overview

• Height: 3–6 ft.
• Growth Pace: Fast Grower, Invasive/Aggressive Grower
• Light: Full Sun to Part Shade
• Moisture: Adaptable
• Maintenance: Moderate
• Characteristics: Self Seeds, Showy Flowers
• Bloom Time: Summer
• Flower Color: Yellow
• Uses: Beds and Borders, Cut Flower, Waterside
• Style: Water Garden
• Seasonal Interest: Summer Interest
• Type: Perennials