Also known as redshank, and Jesusplant, this annual weed is a member of the buckwhat family, Polygonaceae, that also includes sorrel, dock, and rhubarb. It is native to Eurasia from Iceland south to Portugal and east to Japan but was introduced into the US before1843 and as spread throughout eastern US and the northern half of western US. Ladysthumb prefers fertile soil, full or partial sun, and wet to medium moist soil but tolerates less. It is common in disturbed sites such as roadside ditches, moist meadows, vacant lots, abandon fields, edges of yards and gardens, as well as in marshy and riparian areas.
Description:
Growing three feet tall, ladysthumb has smooth or slightly hairy, upright, branching stems with swollen joints. A papery sheath with a fringe of bristles at the upper end encloses each node. The alternate leaves are up to six inches long by one inch wide and often have a brown or black spot in the center. The tiny pink to purple flowers are densely clustered in terminal racemes 1-1 ½ inches long and appear for two or three months in summer. Plants are self-fertile and produce shiny black seeds, the only means or reproduction.
Control:
Mulch to prevent seeds from germinating. Hand pull or hoe young plants and pull, hoe, or mow larger ones before seed set. In extreme cases, selective and non-selective herbicides are effective.