Blue Flag

(Iris versicolor)

Blue Flag (Iris versicolor)

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Estimated Native Range
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Summary

Iris versicolor, commonly known as Blue Flag, is a deciduous perennial herb native to wetlands such as marshes, swamps, and wet meadows, as well as along the edges of ponds and streams in the Northeastern USA and Southeastern Canada. It typically grows 10–80 cm (4–31 in) high and forms large clumps from thick, creeping rhizomes. The sword-shaped leaves provide a vertical accent, while the showy flowers, which are usually light to deep blue, can also display shades of purple and violet. The flowers bloom from May to July and are highly attractive to pollinators. After flowering, the large seeds can be seen floating, which aids in their dispersal by water.

Blue Flag is valued for its striking blue flowers and its ability to thrive in wet conditions, making it an excellent choice for water gardens, rain gardens, and naturalized wetland plantings. It is also used for erosion control along waterways. This Iris prefers consistently moist to wet soils and can even grow in shallow standing water. It is tolerant of part shade but flowers best in full sun. While generally low-maintenance, Iris versicolor can be susceptible to iris borer and fungal leaf spot. It is not invasive but will spread gradually to form a dense cover if conditions are favorable.CC BY-SA 4.0

Plant Description

  • Plant Type: Herb
  • Height: 2-3 feet
  • Width: 2-2.5 feet
  • Growth Rate: Moderate
  • Flower Color: Blue, Purple
  • Flowering Season: Spring, Summer
  • Leaf Retention: Deciduous

Growth Requirements

  • Sun: Full Sun, Part Shade
  • Water: High, Aquatic
  • Drainage: Slow, Standing

Common Uses

Bee Garden, Bird Garden, Border Plant, Butterfly Garden, Deer Resistant, Hummingbird Garden, Low Maintenance, Rabbit Resistant, Rock Garden, Salt Tolerant, Showy Flowers, Street Planting, Water Garden

Natural Habitat

Wetlands such as marshes, swamps, and wet meadows, as well as along the edges of ponds and streams

Other Names

Common Names: Purple Iris , Water Flag , Varied-Color Iris , Harlequin Blue Flag , Larger Blue Flag , Multi-Coloured Blue Flag , Northern Blue Flag , Harlequin Blueflag , Poison Flag , Verschiedenfarbige Schwertlilie

Scientific Names: Iris versicolor , Iris caurina , Iris versicolor f. murrayana , Iris flaccida , Iris boltoniana , Iris dierinckii , Iris picta , Iris pulchella , Iris versicolor f. albocaerulea , Iris versicolor f. versicolor

GBIF Accepted Name: Iris versicolor L.