Amaranthus is the genus of this plant and Amaranthaceae is the family. The genus contains over 60 different species which vary in colour and shape. The flowers and foliage can be green, purple, red or yellow or a combination of these depending on the species. Another type I want to grow in the future is a tricolour variant called, believe it or not, Amaranthus tricolour.
Amaranthus are annual, warm season plants. They are related to Celosias. They are not just used as ornamental plants. Some species are used as food crops. The seed contains protein and the food known as Quinoa is in fact from a plant of the Amaranthaceae family. Flour can be made from Amaranthus seed and the leaves, stems and roots from certain species are also edible. A red dye can also be produced from some Amaranthus plants.