Trimezia martinicensis (Yellow Walking Iris)

  • TropPlant Accession Number (TPAN): 0116
  • Botanical Name: Trimezia martinicensis 
  • Common Name: Walking Iris, Forenoon Yellow Flag, Yellow Walking Iris, Martinique Trimezia
  • Cultivar: N/A
  • Family: Iridaceae
  • Nota Bene: Often misapplied and confused with: T. steyermarkii
Trimezia martinicensis 
Photo by Matthew Gaston

  • Native To: South America, West Indies

Landscaping Information

    • Plant Type: Groundcover, Bulbous
    • Texture: Medium (Strap)
    • Form: Mat
    • Height (on average, in landscape use): 1.5'-3'
    • Height to Spread Ratio: 1:1
    • Growth Rate: Medium to Fast
    • Landscape Values: Background, Border, Filler, Foundation, Groundcover, Mass
    • Outstanding Quality: Flower Color, Form/Silhouette, Laxative 
    Trimezia martinicensis as a groundcover
    Photo by Matthew Gaston


    Botanical Descriptions

    • Flowers: 0.75"-2", Yellow with red or brown dots on claw near throat, no fragrance, three large outer whorled tepals, three smaller inner whorl tepals. Flowers are only open for several hours a day. Flowers borne on an inflorescence 1'-3' high. Scape of inflorescence is shorter than leaves. 
    Trimezia martinicensis flower
    Photo by Matthew Gaston

    • Fruits: Lumpy, Oblong Capsule, 0.75", black seeds.
    • Foliage Color: Young/immature: Bright Medium Green. Mature: Bright Medium Green
    • Foliage Tip: Acute
    • Petiole: N/A
    • Stipules: N/A
    • Margins: Smooth
    • Leaf Arrangement:  Distichous
    • Leaf Shape: Linear to Lanceolate or Ensiform
    • Leaf Type:  Simple 
    • Leaf Texture: Waxy, somewhat thick.
    • Leaf Special Notes: Strap leaves are bright green 

    Trimezia martinicensis 
    Photo by Matthew Gaston

    Horticultural Information

      • Light Preference: Shade to Full Sun.
      • Soil Preferences: Moist
      • Tolerances: Poor Drainage, Submerged Roots, Humidity, Regular Watering
      • Water Requirements: Requires significant moisture, almost standing water.
      • Notes on Maintenance: Flower bloom daily, but only last for several hours. No special care required except very moist conditions. Can become weedy as plantlets form on inflorescences and "walk", which is merely the inflorescence being weighed and bent down by growing plantlets. These plantlets root and can overtake a sufficiently moist area.
      • Propagation: Plantlets, Seeds, Division.
      Trimezia martinicensis "walking"
      Photo by Matthew Gaston

      • Minimum USDA Hardiness Zone: 9a
      • Weed Risk Assessment Score (WRA): Not yet evaluated
      Trimezia martinicensis plantlet grown in hydroponic solution on a desk
      Photo by Matthew Gaston


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