Yellow flag is a vigorous Laevigata iris with ribbed, sword-shaped gray-green leaves. It grows to 3 to 4 feet high. Over 60 cultivars exist, including ‘Beuron’, with evenly yellow flowers; ‘Ecru’, with its off-white blooms; ‘Fresh Cream’, with lovely, pale-yellow flowers marked with red-violet signals; a variegated type, ‘Variegata’; ‘Donau’, a bright-yellow flower adorned with a brown signal that looks like stitchery; and nearly sterile ‘Holden Clough’, with deep-yellow blooms and reddish purple veining.
Noteworthy CharacteristicsExtremely adaptable. Self-seeds freely along streambanks and edges of ponds. Flourishes in both shallow and deeper waters.
CareGrow in full sun to part shade and most any moist soil. Cut flower spikes at the end of the growing season to prevent excessive self-seeding. Sterile cultivars exist.
PropagationLift and divide clumps, or separate bulb offsets, and plant immediately, in early autumn.
ProblemsIris borer, verbena bud moth, whiteflies, iris weevil, thrips, slugs and snails, aphids, and nematodes.
- Genus : Iris
- Plant Height : 3 to 6 feet
- Zones : 5, 6, 7, 8
- Moisture : Adaptable
- Growth Rate : Fast
- Light : Full Sun to Partial Shade
- Maintenance : Moderate
- Plant Type : Perennials
- Characteristics : Self Seeds
- Bloom Time : Summer
- Plant Seasonal Interest : Summer Interest
- Flower Color : Yellow