Blackberry nightshade. Solanum nigrum
Native to Europe
Prefers fertile areas invading edges of rainforest, gullies or protected headlands along the entire coast.
Form: Herb to 1m high.
Flower: Small, white with yellow center, in clusters. Spring to summer
Fruit/Seed: Small purple to black berry, glossy.
Control: Hand-pull before fruit is set. Ensure the entire plant is removed.