Trimezia Species, Forenoon Yellow Flag, Yellow Walking Iris

Trimezia martinicensis

Family: Iridaceae (eye-rid-AY-see-ee) (Info)
Genus: Trimezia (try-MEE-zee-uh) (Info)
Species: martinicensis
Synonym:Cipura martinicensis
Synonym:Iris martinicensis
Synonym:Trimezia connata
Synonym:Trimezia lurida
Synonym:Trimezia meridensis




Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Light Shade

Partial to Full Shade


Grown for foliage



Foliage Color:

Unknown - Tell us


24-36 in. (60-90 cm)


3-6 in. (7-15 cm)


USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

USDA Zone 11: above 4.5 C (40 F)

Where to Grow:

Unknown - Tell us



Bloom Color:

Bright Yellow

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Blooms all year

Blooms repeatedly

Other details:

Unknown - Tell us

Soil pH requirements:

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:

Unknown - Tell us

Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

Seed Collecting:

Unknown - Tell us


This plant is said to grow outdoors in the following regions:

Anniston, Alabama

Apopka, Florida

Bokeelia, Florida

Brandon, Florida

Fort Lauderdale, Florida(2 reports)

Holiday, Florida

Loxahatchee, Florida

Miami, Florida

North Port, Florida

Port Saint Lucie, Florida

Rockledge, Florida

Saint Petersburg, Florida(2 reports)

Summerland Key, Florida

Tampa, Florida

Umatilla, Florida

Venice, Florida

West Palm Beach, Florida

Zephyrhills, Florida(3 reports)

Jesup, Georgia

Charleston, South Carolina

Beaumont, Texas

Christiansted, Virgin Islands

show all

Gardeners' Notes:


On Sep 5, 2021, jumbeecat from Oakland, SC wrote:

Charleston, SC - I have successfully grown this plant in the ground for years. It dies back in winter but as soon as the weather whispers 'Spring' it pops up & continues on. It blooms all summer til frost. If the spent blossoms are left in tact, the weight will eventually bend the stem to reach the ground & the plant walks on. It can also be bent & pinned down manually. It does not spread as prolifically as my blue walking iris.


On May 11, 2013, SCBot from Coronaca, SC wrote:

The correct "scientific" name for this plant is Trimezia martinicensis. Those referring to it as Neomarica have probably just repeated someone else mistake without looking it up more carefully. Both plants make good houseplants if kept humid to prevent tip browning and in warmer climates (Florida) are grown outside.


On Mar 29, 2013, IslandJim from Keizer, OR (Zone 8b) wrote:

Don't understand why Dave's calls this Trimezia martinicensis when every other site I've found calls it Neomarica longifolia. Is it MOBOT or RHS or what?


On Jul 3, 2006, podster from Deep East Texas, TX (Zone 8a) wrote:

Beautiful delicate blooms make this an interesting iris. N. longifolia is not winter hardy so it is kept in a hanging basket. Then, protection can be provided in the winter. This one even blooms during the winter season and throughout the year.


On Jun 18, 2005, sundry from Franklin, LA (Zone 9a) wrote:

This is one of my favorite plants. Very cheerful, blooming abundantly almost year round, if protected from hard freezes. The foliage is upright and seems to dance in every breeze. It's an eye catcher. And way too easy to grow!


On Jul 2, 2004, punaheledp from Kailua, HI (Zone 11) wrote:

One day a few years ago my neighbor and I traded her yellow for my blue (gracilis) over the fence. Like both very much and both do very well. Yellow is hardier and a year round prolific bloomer. I've always let them spread by runner, but can probably collect seeds too as mine currently have many pods. I like both together with yellow in back as it's leaves are more upright and taller, a lighter matte green while the blue's are glossy and curve softly down. They do well in both sunny and semi-shady area of my garden.


On May 24, 2004, purplepetunia from Savannah, GA (Zone 8b) wrote:

I have had this plant for years and shared it with many people. It will die back in the winter, but then a lot of it comes back in the Spring.


On Dec 29, 2003, Jamespayne from Sebring, FL (Zone 9b) wrote:

I lived in Tampa in the early 1980's, and rented a house with a bricked in flower bed with nothing but weeds. I pulled up the weeds, and at the time I had several large aquariums in my home. When I cleaned my aquariums, I let the water run into the empty flower bed. Suddenly green shoots started coming up all over the flower bed. I had discovered Neomarica Longifolia and have this plant to this day, although I have moved several times. I always took some off-set "pup" plants with me to my new home. Now that I have bought a home, they are all over my yard and I give them to people who ask what type of plant I have. People who kill plants, can raise this plant with ease. Neomarica Longifolia can tolerate more sun than the Neomarica Gracilis, and it can be drought tolerant. Blooms all year lo... read more


On Oct 5, 2003, TerriFlorida from Plant City, FL wrote:

In 1989 I inherited a pot of tall upright flexible medium green leaves. I had no clue what it was. The pot was shallow and broken, the plant did not care -- my kind of plant. I set it in the garden in part shade, similar to where I'd found the pot in the previous owner's yard. It rewarded me with cute little yellow flowers for months. It rewarded me with plantlets which grew where each flower had been. As the plantlets grew, they weighed down the stem until the farthest one touched dirt. It rooted. So I popped off some of its mates and stuck them in the ground. They rooted. So I made pots of these plants and gave them away. This plant and I have spent years increasing its population all over the county, ha-ha. It is easy to pull where you don't want it, it eventually forms a foot wide clum... read more


On Apr 23, 2003, easter0794 from Seffner, FL wrote:

This is an easy to grow plant. It flowers all spring and summer long. Sends out shoots that lay down and root into baby plants (walking). It looks great around my pond and does very well without fertilizer.


On Apr 11, 2003, leslied from Pompano Beach, FL wrote:

Sold as Louisiania Walking Iris in most nurseries here - zone 10b. Easy to grow, spreads through shoots which lay down - then root.