Mexican Primrose Willow

Ludwigia octovalvis

Other common name(s):

Mexican Primrose-willow, Narrow-leaf Water Primrose, Seedbox

Family:

Onagraceae (Evening Primrose Family)

Plant Ecoregion Distribution Map

Edwards Plateau, Gulf Coast Prairies and Marshes, Southern Texas Plains, Texas Blackland Prairies, Western Gulf Coastal Plain
Balcones Canyonlands, Edwards Plateau Woodland
Lower Rio Grande Alluvial Floodplain, Lower Rio Grande Valley, Northern Humid Gulf Coastal Prairies, Texas-Louisiana Coastal Marshes
Northern Nueces Alluvial Plains, Rio Grande Floodplain and Terraces, Semiarid Edwards Bajada
Floodplains and Low Terraces1, Northern Blackland Prairie, Southern Blackland Prairie
Flatwoods, Southern Tertiary Uplands

Plant Characteristics

Growth Form

Shrub, Wetland

Height

3
to
6
ft.

Spread

3
to
6
ft.

Leaf Retention

Semi Evergreen

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Moist, Mud

Light Requirement

Sun, Part Shade

Water Requirement

Medium

Native Habitat

Wetland or Riparian

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Summer, Fall

Seasonal Interest

Nectar, Larval Host

Wildlife Benefit

Butterflies, Moths

Maintenance

A swamp or wetland plant that needs moist or shallow, submerged soils. It is fast growing and reseeds heavily. May need periodic trimming to control spread in small spaces. Leaves may turn red as the plant ages. Can be grown in a container. Set up a pond or a water collection tank near a downspout to supplement water. Propagation: root cutting.

Comments

Blooms June-October. Ribbed stems are erect and branched, sometimes woody at the base. Leaves are lance-shaped to ovate, with sunken venation and a reddish to pale midrib. Bright yellow, solitary flowers arise from leaf axils. They close in the evening and reopen in the morning. The fruit is a capsule that opens irregularly. Nectar attracts butterflies. Larval host: Water-primrose Hornworm Moth.

References

1) Griffith, Bryce, Omernick & Rodgers (2007). Ecoregions of Texas. 2) https://www.wildflower.org/plants/result.php?id_plant=LUOC. 3) http://bonap.net/TDC/Image/Map?taxonType=Species&taxonId=15705&locationType=County&mapType=Normal. 4) https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=503565#null, 5)
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About the Region

New Braunfels, the location of our Fall 2024 Symposium, straddles both the Edwards Plateau Ecoregion and the Blackland Prairie ecoregion. Interstate 35 divides the city of New Braunfels; its path through the city closely parallels the boundary of these two ecoregions, with the Edwards Plateau on the west side and the Blackland Prairies region to the east. The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our four host chapters (New Braunfels, Lindheimer, Guadalupe, and the Hill Country chapters) are located in one or both of the ecoregions above. However, the eastern portion of Guadalupe County also falls within the Post Oak Savanna ecoregion. Annual rainfall averages 35 to 45 inches, with higher averages to the east. A wide variety of hardwood trees are found, including several species of oaks, elms, and in the Bastrop area, loblolly pine (Pinus taeda). Grasses and forbs dominate in the open savannas, with most common grass being little bluestem. Ranching, agriculture, and fire suppression have allowed woody species to encroach on the once-open savannas.

Source: Wildflowers of Texas by Michael Eason