The perennial stinging nettle (Urtica dioica) is a perennial, herbaceous plant with creeping roots. It is perhaps most troublesome in loose, newly cultivated soil, especially where phosphate levels are high. The creeping surface stems can extend for some considerable distance, rooting at the nodes and producing aerial shoots.
The annual nettle does not have long-lasting roots, but does produce very large numbers of seeds from an early age. Like its perennial realtives, it relishes fertile soils rich in organic matter and is a serious weed in vegetable gardens.
Nettles are very tolerant of extreme climatic conditions, germinating readily from seeds. Individual plants or clumps are either male or female and when both sexes are growing close together female plants produce large numbers of seeds.