Scleranthus annuus, commonly known as German knotweed or annual knawel, is an annual or biennial herb that is native to a variety of habitats including grasslands, open woodlands, and rocky slopes in Europe, Asia, and North Africa. It typically grows to a modest height of up to 6 inches (15 centimeters) and forms dense, mat-like patches. The plant has tiny, inconspicuous green flowers that may go unnoticed, blooming from late spring to early autumn. Its foliage is bright green and needle-like, adding a fine texture to garden settings.

German knotweed is valued for its low-growing, ground-covering habit, which makes it useful for filling gaps in rock gardens, green roofs, and as a living mulch to suppress weeds. It thrives in poor, sandy, or rocky soils with good drainage and prefers full sun to part shade. While it is drought-tolerant once established, it benefits from occasional watering during prolonged dry spells. Annual knawel is not commonly affected by diseases or pests, but it can self-seed prolifically, which may lead to unwanted spread in the garden.CC BY-SA 4.0