Clematis 'Royalty'

Clematis 'Royalty' was raised in 1985 by English breeder John Treasure from a cross between 'Maureen' and 'Countess of Lovelace'. Its 10-12 cm flowers open dark violet-blue with a paler central bar and dark veins, set off by purple-yellow stamens; the season's first flowers appear attractively semi-double, with densely overlapping, rounded tepals.

'Royalty' flowers first in June, followed by a second flush from July to August. At around 250 cm, the variety suits trellises, obelisks and other supports well, but also thrives in a sufficiently large container (at least 45 cm deep and wide). It grows best in a sunny to semi-shaded position; keep the root area cool and shaded, for example with ground cover or a layer of gravel.

'Royalty' is reliably winter-hardy (zone 6, down to about -23 °C) and was awarded the Royal Horticultural Society's Award of Garden Merit. Cut the plant back to about 100 cm in June – since the first, semi-double flowers already appear in early summer, only light pruning is needed afterwards so the late-summer flush is not lost.