Native to Europe, but introduced to the western United States, where it occurs sporadically in California, Idaho, and Utah.
Very similar to the common Hyssop loosestrife and found in many of the same habitats, preferring moist soils along roadsides, pastures and waste areas. A summer annual or short-lived perennial that reproduces from seeds.
Mature plants may be erect when growing amongst competitive vegetation, or prostrate and spreading when growing in an open area. Stems are somewhat square, and may grow to 24 inches long. Stems are green to slightly reddish, and this color becomes even more noticeable in plants that over-winter, when the leaves also attain a purple caste.
Leaves are narrow, pointed, to just over 1 inch long, and slightly fleshy. They attach to the stem with no stalk and are alternating along the stem. Flowers are small and white to pale purple, and they arise from the axil at the base of the leaf. Flowers have 5 to 7 petals.
Characteristicts Important to Control:
Physical removal of individual plants can be effective. When growing in landscape a contact or systemic herbicide will kill the plants, and a pre-emergent herbicide can effectively prevent seed germination.