Plants in genus lythrum
Lythrum alatum
Lythrum alatum is a herbaceous plant native to wetland areas in the central and eastern United States and Ontario. It features upright, branching stems with square cross-sections and winged angles, and its leaves are opposite, stalk-less, and broadly oblong. The plant produces rose-pink flowers with magenta central veins and is endangered in several states. It forms bushy clumps up to 3 feet wide and 3.5 feet tall, preferring moist soils and wet environments.
Lythrum virgatum
Lythrum virgatum is a native perennial with fine-textured foliage in green and bronzy-purple, producing nodding yellow star-shaped flowers. It prefers moist soils and can tolerate rocky and gravel conditions. This plant is hardy in USDA zones 4 to 8 and thrives in full sun to partial shade.