This shrubby perennial (ht 75cm) from South America, Heliotropium arborescens, is colloquially known as heliotrope or cherry pie. The tiny clustered flowers have a delicious vanilla fragrance. There are various forms with different flower colours, most commonly purple, but lilac and white cultivars can be found. The cultivar 'Lord Roberts' (pictured above) has very rich purple flowers.
One cultivar, 'Aurea' (pictured left), is grown for its golden leaves, which will appear lime-coloured in part-shaded sites and has scented mauve flowers, but the primary attraction is the broad, soft foliage. Like most gold or lime leaves, it is a brilliant partner to blue or purple flowers (such as Salvia, Ajuga or Aquilegia, or can be used to echo nearby yellow blooms.
Heliotrope likes sufficient water and well-drained soil, but it is quite a tough plant and seems to survive our summer heatwaves fairly well. It will flower best in a sunny spot. It benefits from regular deadheading of spent blooms and a harder prune around September. I have seen heliotrope trained as a standard plant. In suburbs with severe frosts, heliotrope may be burnt in winter. Like many shrubby perennials, the plant will eventually become tired and woody: then it is best to replace it with a new specimen. It can be a bit tricky to propagate from cuttings, in my experience!
Note that another species, Heliotropium amplexicaule, commonly known as blue heliotrope, is a serious invasive weed in rural areas, and should not be cultivated as a garden plant.
Heliotropium belongs to the family Boraginaceae.