Scientific name: Cotinus coggygria ‘Royal Purple’
Common names: `Royal Purple’ Smoketree, `Royal Purple’ Wig-Tree, `Royal Purple’ Smokebush.
Plant breeder: Lombarts Nursery – Boskoop, Holland
`Royal Purple’ Smoketree is perhaps the most popular bush among the plant varieties of red in the leaves. It is a perennial woody deciduous shrub or small tree of moderate size and slow growth, whereas in relation to the typical species it is smaller in dimensions.
Its height varies between 4 to 5 m (13-16 ft) – in ideal conditions it can also catch 6.5 to 7 m (21-22 ft) – and its diameter between 3 to 4 m (9-13 ft), dimensions in which it will reach at the age of 10 to 20 years.
Its canopy is spherical-ellipsoid, relatively open and symmetrical, more in young plants, while it has a medium texture and upright appearance.
`Royal Purple’ Smoketree reaches approximately 50 years, while older plants are also reported.
The plant at a young age develops from the base many upright and moderately branched shoots. Their color is initially green with some reddish shades, but maturing becomes brown. Brown to gray-brown is also the color of the bark, whose texture is relatively rough.
The leaves are simple, alternate, ovate-obovate in shape, with smooth edges, and a length of between 3.8 and 8.9 cm (1.5-3.5 in). Their color is dark reddish purple – the darkest of all red varieties of Smoketree – while in autumn they get a strong orange and red-purple hue. Characteristic of ‘Royal Purple’ in relation to leaves is that their color remains unchanged whether planted in hot or cold areas.
Flowers appear at the end of the spring with early summer in a 15-20 cm panicle inflorescence . They are yellow and small, consist of 5 petals and do not special attract insects.
The fruits are brown drupaceous laterally pressed, their shape on the front view is irregular oval and their color orange-brown. Their length is 1-1,2 cm (0.4-0.6 ft) and they are devoid of decorative value.
The `Royal Purple’ Smoketree variety is less resistant to cold than the typical species and less resistant also, of all red varieties. It can withstand low temperatures up to -21 °C (-5 °F – USDA Hardiness zone 6b), while showing good performance at the high temperatures of the areas of the Mediterranean vegetation zones.
In terms of soil, it prefers dry, medium texture and poor, whereas its acidity or alkalinity does not seem to play an important role in selecting the appropriate pH range.
In relation to the exposure, it can be planted in both sunny and semi-shady places, but if there is a possibility it is better to avoid the latter because the plant grows asymmetrically, damaging its ornamental value.
From insects, it generally does not deal with serious problems, while diseases refer to Powdery mildew and Verticillium wilt. By using the appropriate formulations, they are treated satisfactorily.
Pruning, due to the slow growth of ‘Royal Purple’, is not a necessary job, especially in the early years of its planting. Later, a moderate pruning every 1 to 2 years can take place, as it helps in a more compact appearance of the bush.
Finally, it is worth mentioning that the `Royal Purple’ Smoketree variety has received, in 1993, the Garden Merit Award from the Royal Horticultural Society.
The use of the material, where third-party rights are not mentioned, is absolutely free. Its sharing, possibly, useful.
This cultivar of Smoketree is suitable for:
In the following video, some information is given on Cotinus coggygria, which generally apply to ‘Royal Purple’ Smoketree.