红桑（学名：Acalypha wilkesiana），又名威氏铁苋，为大戟科铁苋菜属下的一个植物种。

Acalypha wilkesiana is an evergreen shrub. It grows 3 m high and spreads 2 m across. The stem is erect with many branches. The branches have fine hairs. It has a closely arranged crown. The leaves are coppery green with red splashes of colour. This gives them a mottled appearance. The leaves are large and broad with teeth around the edge. They can be 10–20 cm long and 15 cm wide. The leaves are finely hairy. They can be flat or crinkled. The flowers are reddish in spikes at the end of branches. They have separate male and female flowers on the same plant. The male flowers are in long spikes which hang downwards while the female flowers are in short spikes. They do not show up easily as they are often hidden among the leaves. The flower stalks are 10–20 cm long.