Written by Maggie
Mar 02 2021
Mexican primrose-willow (Latin name: Ludwigia octovalvis (Jacq.) Raven) is a stout, erect perennial herb belonging to Polygonum polygonum of the Willow family. Mexican primrose-willow is from the tropical and subtropical regions. Mexican primrose-willow was born in fields, lakes, valleys and open to wet places, elevation 0-750 meters.
Mexican primrose-willow is an annual herb. Seedling is prostrate on the ground, or for decumbent, after pumping the stem upright, 20 ~ 50 cm long. Stem is angular, more branching, branches with square, to the autumn stem and leaves are purple, all smooth hairless. Leaves of Mexican primrose-willow are simple alternate; Leaf blade is lanceolate, 4 -- 7.5 cm long, 1 -- 2 cm wide, apex acuminate, entire, base attenuate, petiole less than half as long as leaf blade.
Flowers of Mexican primrose-willow are axillary, usually 1 to 2, sessile; Calyx is 4-5-lobed, lobes ovate, ca. 2 mm long, with fine hairs outside, persistent; Petals are as many as calyx lobes, elliptic, ca. 3 mm long, apex obtuse, base narrow, short clawlike, decolorated; Mexican primrose-willow has 4-5 stamens; Ovary is inferior, outside densely hirsute, 4-loculed, style short, stigma simple, capitate.
Capsule of Mexican primrose-willow is linear square, erect or slightly curved, truncated at both ends, 15 -- 20 mm long, purple at maturity; Seeds are small, smooth, brown - yellow.
Mexican primrose-willow was born in fields, lakes, valleys and open to wet places, altitude 0-300 (-750) meters.
Mexican primrose-willow distributes in Jiangxi, Zhejiang, Fujian, Taiwan, Guangdong, Hong Kong, Hainan, Guangxi, Yunnan. Asia, Africa, Oceania, South America and the Pacific islands are also widely distributed in the tropical and subtropical areas.
Water care: Medium
Light care: Sun , Part Shade
Soil Moisture: Moist
Conditions Comments: Mexican primrose-willow is a shrubby herbaceous plant that grows well in moist or shallow, submerged soils. The one inch, bright yellow flowers are numerous in the summer months and look great in a pond with other plants like Swamp Milkweed, Powdery Thalia, and Scarlet Rose-Mallow. It is fast growing and reseeds heavily. May need periodic trimming to prevent them from growing too large and overcoming other plants. Host plant for the Mexican primrose-willow hornworm moth, caterpillars and moths that are spectacular to see.