CERATOSTIGMA WILLMOTTIANUM (Chinese Plumbago)
W China
Its dense mass of small, purple-margined leaves makes this shrub from China a handsome one. Ceratostigma Willmottianum likes warmth and a sheltered position out of the wind. In late summer, masses of intensely BLUE flowers, much visited by bees, cover the plant. They bloom until first frosts, when the leaves turn red.
Soil that is not enriched, but more impoverished, brings out the best in its cobalt-blue flowers. Carol Klein, writing in The Telegraph, reckoned that Hummingbird Hawkmoths are even better than late season Butterflies at extracting nectar from its flowers.
www.telegraph.co.uk/gardening/3324366/How-to-grow-Ceratostigma.html
https://www.rhs.org.uk/Plants/3411/Ceratostigma-willmottianum/Details
‘Ceratostigmas are found naturally on the rocky slopes of hot, dry valleys, often in rain shadows, and therefore demand good drainage and an open, sunny position in the garden. In cold areas where winters are long, ceratostigma is best grown in a sheltered position against a sunny, south-facing wall.’
Val Bourne in The Telegraph
http://www.telegraph.co.uk/gardening/howtogrow/3345154/Chinese-plumbago-How-to-grow.html
The Chinese Plumbago is a native of the Himalayas. Here in North London, planted behind the Ecology Centre in Gillespie Park, it does well at the base of the rock garden slope.
My friend Anne has it in her west-facing raised bed in Wimbledon, where it flourishes in a sheltered position behind the birdbath and her ‘lawn’ of ‘Mind Your Own Business’. It fills the bed with a late summer haze of fabulous blue flowers.