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Trimezia steyermarkii R.C. Foster

Family Name: Iridaceae
Synonyms: Neomarica longifolia (misapplied)
Common Name: Yellow Walking Iris
Full Sun: 6-8h Semi-Shade Lots of Water Moderate Water Ornamental Flowers Ornamental Foliage Dry Soils / Drought Herbaceous


Family Name
Genus Epithet
Species Epithet
Name Authority
Name Status (botanical)
Common Names

Classifications and Characteristics

Plant Division Angiosperms (Flowering Seed Plants) (Monocotyledon)
Plant Growth Form Herbaceous Plant
Mode of Nutrition Autotrophic
Maximum Height 0.9 m to 1.2 m


Native Distribution Mexico to Venezuela

Description and Ethnobotany

Growth Form Herbaceous rhizomatous shrub that grows in grassy clumps, up to 1.2m height.
Foliage Flat strap-like leaves, arising in fan-like arrangement from underground rhizomes.
Flowers Iris-like, bright yellow with prominent mottled brown spots, with 3 bigger outer petal segments, produced on top of rounded infloresence stalks that arise from base of plant. Flowers short-lived, lasting only 1 day and curling up in the evening, but plant is free-blooming.
Others - Plant Morphology Aerial Plantlets: Produced from spent inflorescences, which arch towards the ground with weight of growing plantlets, and allowing these to take root upon contact with ground.
Habitat Low-nutrient, well-drained soils and forest debris in humid areas.
Similar Resembles and often misidentified as Neomarica longifolia or Trimezia martinicensis. Differentiated by shape of infloresence stalks -- Trimezia has rounded flower stalks and leaf axis, while those in Neomarica are flattened. Trimezia steyermarkii has larger yellow flowers with brown spots, but Trimezia martinicensis has smaller pure yellow flowers. All 3 species mentioned here are different species, although often confused and used interchangeably with one another. Most of the commonly-cultivated plants known horticulturally as Neomarica longifolia are actually Trimezia steyermarkii .
Cultivation Hardy species, fairly easy to grow, withstands waterlogged soils but also drought-tolerant when established. Withstands alkaline soils of pH 6.6 - 7.8. Propagate by division of clumps, rhizomes or aerial off-sets.
Etymology Genus epithet 'Trimezia' derived from Greek terms "treis" (three) and "megas" (great), a reference to the distinctive flowers, whose 3 outer segments are bigger than the inner ones. Species epithet 'steyermarkii' named after American botanist Julian Steyermark (1909-1988) who specialized in New World flora, especially those in Missouri, Venezuela and Guatemala, and collected more than 130,600 plants from 26 countries during his lifetime, earning him an entry in the Guiness Book of World Records. Common name 'Walking Iris' refers to the plant's characteristic of producing plantlets that take root upon ground contact, thus helping the plant propagate itself by "walking".

Landscaping Features

Desirable Plant Features Ornamental Flowers, Ornamental Foliage
Plant & Rootzone Preference - Tolerance Waterlogged Soils (Drains Site), Dry Soils / Drought, Fertile Loamy Soils, Well-Drained Soils
Landscape Uses Parks & Gardens, Flowerbed / Border
Thematic Landscaping Golden Garden

Plant Care and Propagation

Light Preference Semi-Shade, Full Sun
Water Preference Moderate Water, Lots of Water
Maintenance Requirements Moderate
Propagation Method Storage Organ, Division, Aerial Plantlet


Foliage Retention Evergreen
Mature Foliage Colour(s) Green
Mature Foliage Texture(s) Smooth, Thin
Foliar Type Simple / Unifoliate
Foliar Venation Parallel
Foliar Margin Entire
Leaf Area Index (LAI) for Green Plot Ratio 3.5 (Shrub & Groundcover - Monocot)

Non - Foliar and Storage

Stem Type & Modification Acaulescent
Root Type Underground (Fibrous Root)
Specialised Storage Organ(s) Underground (Rhizome)

Floral (Angiosperm)

Flower & Plant Sexuality 1 Bisexual Flowers
Flower Colour(s) Brown, Yellow / Golden
Flower Symmetry Radial
Flowering Period Free-Flowering
Flower Lifespan on Plant 1 Day
Flowering Habit Polycarpic

Image Repository



Master ID 967
Species ID 2261
Flora Disclaimer The information in this website has been compiled from reliable sources, such as reference works on medicinal plants. It is not a substitute for medical advice or treatment and NParks does not purport to provide any medical advice. Readers should always consult his/her physician before using or consuming a plant for medicinal purposes.
Species record last updated on: 20 April 2020.