(Solanum nigrum) Depending on conditions and climate Black Nightshade may be annual or a short-lived (2-3 years) perennial of about 80cm in height. It is widespread both in Australia and other countries, originating in Europe, Asia and northern Africa. One of Australia's worst weeds of broad acre horticulture, it competes vigorously for space and nutrients, especially in Solanaceae crops such as tomatoes. It is also known to be a host to numerous nematodes, fungi and viruses that indirectly threaten associated crops. Its green (immature) fruit and leaves may at times contain toxic alkaloids. The berries ripen to dark purple, almost black, and contain multiple seeds, the most common method of spread.