Clematis patens Royal Crown

Clematis 'Royal Crown', also known as 'Haku Ookan' or 'Hakuokan', is a lovely Japanese variety that produces large and beautiful star-shaped flowers in shades of purple to dark blue-violet, adorned with a magnificent bouquet of white stamens with pale-yellow anthers. These flowers are often semi-double at the beginning of flowering, then single. It is a medium-sized variety, but vigorous. It blooms from late spring to late summer. It will find its place in gardens of all sizes, as well as on patios and balconies, planted in a large pot. 

Clematis belong to the Ranunculaceae family. They can be found in Europe, the Himalayas, China, Australia, and North and Central America. The 'Royal Crown' variety, with unknown parentage, was obtained in 1957 by Yashio Kuboto. It is a perfectly perennial, semi-woody, climbing plant that will reach a height of approximately 3.50m (11ft), with a minimum spread of 1.5m (5ft). This clematis bears large, fully open flowers that can reach 15 to 18cm (6 to 7in) in diameter. They appear in successive waves on the new shoots from May-June until the end of summer. The flowers are solitary and have pointed, inwardly curved tepals in intense violet with bluish reflections. The centre of the flower is adorned with a beautiful crown of stamens with a white base and pale-yellow anthers. The flowering is followed by decorative silver-grey feathery fruits that persist until winter. The glabrous leaves are divided into 3 elliptical to lanceolate leaflets that are dark green in colour. This clematis firmly attaches itself to the support or host plant through petioles that are transformed into tendrils.

Plant your clematis alongside climbing or rambling roses ('New Dawn', 'Mme Caroline Testout', 'Zephirine Drouhin') to extend the flowering season of walls and pergolas until the end of summer. It is a diverse genus, with flowers of all colours, shapes, and sizes. Take advantage of their easy cultivation to give your garden a romantic and bohemian touch. It will pair well with the blue flowers of C. Hudson River, the violet flowers of C. 'Romantika', or the red flowers of C. 'Rebecca' or C. 'Rouge Cardinal', for example, climbing a fence or covering a wall exposed to the morning sun.

Avoid excessive use of fertilisation, as it stimulates foliage growth at the expense of flowers. Do not mulch in order to prevent excessive moisture.