Annual over wintering seed-propagated weed germinating in the fall and spring (year round). Forms thick mats in mild winters. Prefers friable, well-aerated, moist but not waterlogged, slightly acidic to alkaline, nitrogen-rich soils.
Cotyledons are narrow, ovate to lanceolate (lance shaped), pointed, the petiole (stalk) is as long as the blade (Picture 1). True leaves are delicate, light green, rounded to ovate with pointed tips, petiolate, opposite, with entire margins (Picture 2). The flowers are small and grouped in loose cymes. The 5 white petals are deeply divided and the flower may therefore appear to have 10 petals (Picture 3). The number of seeds per plant can be as high as 15,000. The seeds are rounded, reniform, reddish-brown to black, with barbs on the back (Picture 4). Studies have shown that the seeds remain viable in the soil anywhere from 6 to 68 years. Germination takes place as low as 2 °C, but the optimum temperature is 13 to 20 °C.