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Graham Rice on Trials

Updates on trials and awards from the Royal Horticultural Society by Graham Rice

First season stars in the Wisley clematis trial

Posted by Graham Rice on 25 Nov 2009 at 02:52 PM

Clematis 'Jorma' - star of the Wisley clematis trial. Image: ©GardenPhotos.comNow that the assessment panel - which includes some of the country's leading experts in shrubs and climbers - has finished this year's sessions on the trial of Clematis viticella varieties, it's a good time to pick out those which they think have done best this year. I gave an early personal assessment, but the team has been checking the trial all summer right into the autumn.

The star of the show so far has been ‘Jorma' (left, click to enlarge).  Its beautiful bluish-violet flowers were especially impressive and very uniform in colour with attactive stamens. However, the view was that this is not really a Viticella clematis but a Jackmanii type.

Two old also favourites did well. ‘Alba Luxurians', white with green marks, was at its peak in mid August and still impressive a month later while the wine-red ‘Kermesina' also proved long flowering - its long season perhaps distinguishing it from the otherwise similar ‘Rubra'.

Clematis 'Romantika' - a highlight of the Wisley clematis trial. Image: ©GardenPhotos.comSimilar to ‘Alba Luxurians' was ‘Luxuriant Blue' (entered as ‘Caerulea Luxurians') but with a blue tint to the white and green flowers indeed ‘Alba Luxurians' is one of its prents (the other is the rarely seen ‘Neodynamia').

The deep purple blue ‘Blue Belle' proved better than the rather similar ‘Kiev' but became rather lanky later in the season while ‘Elvan', with pretty purple flowers striped in white, has nodding flowers so is best viewed from below. It was another with a very long season.

‘Hagelby Pink' was the best pink this year, and still had plenty of buds coming in mid September. It also flowererd all the way up the plant, a valuable feature. The panel agreed that it would look growing with the dark purple ‘Romantika' (above, click to enlarge), another Jackmanii type, which also stood out this year.

In general the assessors noted that watering was a big help in extending the flowering period of these plants; on the trial this was provided soil level irrigation. But they decided that now that the plants are well established, next year they would not be watered unless absolutely necessary. This would provide a more realistic test.

The plants will all be cut back to 15cm/6in in the spring - just as they would be in the garden. Next year's display promises to be even more colourful.



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