Scleranthus annuus is a species of flowering plant in the family Caryophyllaceae known by the common names German knotweed and annual knawel.

[1] It is native to Europe, Asia, and North Africa, and it is known throughout the rest of the temperate world as an introduced species and a common weed.

Scleranthus annuus is an annual or biennial herb with low, much-branched spreading stems up to 15 cm (6 in) long growing from a taproot.

The flowers make little effort to attract insects for pollination (no showy petals, little nectar), and most are self-pollinated.

[1] This plant is in decline in many of its previous habitats and is no longer present in many inland sites in Britain and Ireland.