Warrigal Greens (also known as New Zealand Spinach, Botany Bay Spinach, among others). Tetragonia tetragonoides.
This leafy, fast-growing vegetable is native to Eastern Asia, Australia and New Zealand.
It is a hardy plant that can handle most soil types. It prefers a full sun position with good air movement and it should grow to about 30cm high by 90cm wide.
You can harvest the leaves all year round. Blanch or steam them before eating.