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Graham Rice on Trials

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

Intriguing ipomoeas

Posted by Graham Rice on 07 Oct 2009 at 03:54 PM

The trial of annual climbers at Wisley has thrown up some stars and some disappointments. Both extremes are to be found amongst the ipomoeas.

Mina lobata in the Annual Climbers trial at the RHS Garden at Wisley. Image: ©GardenPhotos.comIn recent years botanists have decided that, although superficially it looks very different, Mina lobata is so closely related to Ipomoea that it should be moved into the genus Ipomoea as Ipomoea lobata (left, click to enlarge). It's been a real star, with spikes of flowers featuring bright red buds opening to cream. Three very similar entries were included in the trial and in recent weeks all three have been stunning and all three look to be on track for an Award of Garden Merit. And all three looked impressive all day.

Also pretty impressive was Ipomoea ‘Ismay Soft Blue' (below, click to enlarge), with its white flowers neatly barred in blue and late in the season it seemed to have the most flowers on show of any ipomoea. Ipomoea 'Ismay Soft Blue' in the Annual Climbers trial at the RHS Garden at Wisley. Image: ©GardenPhotos.comThe deep purple ‘Kniola's Black Night', with its white throat, set against small, dark foliage was also good. This and the other familiar trumpet-flowered ipomoeas all open very early in the day and on hot sunny days have crumpled by lunch time although on cool days ‘Ismay Soft Blue', in particular, lasted till the end of the day.

However our old favourite ‘Heavenly Blue' - such a stunning colour - and many of the other ipomoeas proved too leafy on the rich Wisley trials field soil and, as happens with nasturtiums, the leaf stalks stretch and so the leaves tend to hide the flowers. The same thing happened with the thunbergias. The ipomoea leaves themselves also grew larger than normal and there seemed to be far more of them. The result of all this extended leafy growth was that the flowers were often hidden. Some were also rather variable in their flower colour or patterning and these included ‘Flying Saucers' and ‘Azzurro di Venezia'.

Those Ipomoea lobata may have started later than most of the annual climbers but the autumn display is amazing.



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