Smoketree Cotinus 'Royal Purple' on stem purple - Hardy plantA sphere of leaves on top of the stem. We love the smoketree 'Royal Purple' (Cotinus coggyria). The Cotinus has purple foliage. In the autumn, they turn orange brown. Cream coloured flowers bloom on the tree in late spring. Position the plant in a sunny spot. The smoketree prefers well drained soil. Keep the soil slightly moist at all times, however, the plant can also handle being dry for a short period.