Water primrose is a creeping or floating aquatic perennial herb. The
leaves are alternate, simple, and net-veined. The petiole is 1-5 cm long,
and the blade is elliptic to obovate with entire margins. The flowers
are axillary, perfect, and solitary. The five petals are yellow. The fruit
is a capsule with many seeds. The seeds are ellipsoid, yellowish, and
shorter than 1 mm.
Plants grow in ditches, ponds, streams, rice fields, marshes, and other
freshwater habitats. It is a fast-growing plant that can reproduce by
seeds and asexually by rooting at the nodes.
The fast-growing habit allows water primrose to choke out natives and
also hinder man's activities such as water travel, irrigation, etc. The
dense above-water growth can also be a home for nuisance and disease-bearing
I took this picture of Ludwigia pelploides at the Lewisville Aquatic
Ecosystem Research Facility (LAERF). This plant flowers in Mid-May and
produces brilliant five-pedaled yellow flowers in the nearshore aquatic
vegetation. I've seen it in drainage ditches and pond-edges forming large
matas of floating vegetation.
primrose will spread along the water surface via runners as seen here.
These runners have roots that act to bring in nutrients and water. Often
the runner stems are reddish color while the leaves are green