Oxalis bowiei

Oxalis bowiei, Bowie's wood-sorrel, red-flower woodsorrel, or Cape shamrock, is a plant from the genus Oxalis, which is native to what was Cape Province and KwaZulu-Natal in South Africa. It has also been naturalized in Australia.
It is named after James [Bowie (botanist)|James Bowie] who collected plants for the Royal [Botanic Gardens, Kew] at the beginning of the 19th century.
Its flowering stems may be a foot or more in height and are produced continuously for a considerable length of time during summer.