Welcome (or not) to the immigrant from South America, Heliotropium amplexicaule. It is naturalised in South Africa, in places like the Pretoria (Tshwane?) region and possibly KwaZulu-Natal. Here for keeps as a garden escape, it grows in grassland and places where the natural vegetation has been disturbed.

About 19 of the 150 species of the Heliotropium genus are indigenous to South Africa, for instance the white-flowering A. steudneri, commonly known as the string of stars.

H. amplexicaule is a low-growing perennial herb upon a woody rootstock, a taproot. Only the tips of its long, prostrate and hairy stems curve up.

In parts of Australia some pest control methods using beetles have been explored to reduce the infestation by this plant (Pooley, 1998; Van Wyk and Malan, 1997; Wikipedia).