What is it? A vigorous clematis that's perplexingly rare. It flowers from late summer into autumn, producing an array of lemon-yellow, bell-shaped flowers that look like fairy skirts. This one's a romper, and will happily colonise a house wall or fence if given sturdy support. It's fully hardy, so no need to panic about protection in winter.
Plant it with? Clematis rehderiana (if, like me, you can't bear calling it by its common name) is rather too dominant a plant to brook much competition, but you could try giving it an evergreen backdrop for the winter months, such as ivy.
And where? At the gardens at RHS Hyde Hall it's grown against a north-facing wall: the roots need shade, although the upper regions will benefit from a few hours' sunbathing a day. If it gets out of hand, prune back the old stems in February or March, to the lowest pair of healthy buds.
Any drawbacks? This is one big plant once it gets cracking: a drawback only if you lack the space. Allow for an eventual height and spread of 7m x 3m.
What else does it do? The flowers smell of cowslips, and bees and butterflies love it.
Buy it Order one plant for £11.99 or two for £17.98 (prices include free UK mainland p&p). To order, call 0330 333 6856, quoting ref GU90, or visit our Reader Offers page. Supplied as 7cm potted plants; delivery from September.