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Graham Rice on Trials

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

Top wisterias in the trials

Posted by Graham Rice on 30 Jun 2009 at 04:17 PM

Wisteria sinensis 'Amethyst' on trial at Witch Hazel Nursery. Image: ©Wendy Wesley/RHS Trials OfficePlenty of shrubs and climbers have been at their peak recently including wisterias, honeysuckles, lilacs, Berberis, as well as the less well known Indigofera, Desmodium and Lespedeza, and the panel that assesses these plants have been busy.

The wisterias were assessed at two sites near Wisley, Witch Hazel Nursery which houses one of the two National Collections, and the garden at Pyrford Court which is not open to the public. The plants have been growing for six or seven years now, this is the second year of assessment and some plants are emerging as likely AGM candidates.

One interesting observation, which will help all of us identify mystery plants in our own gardens, was that W. sinensis, W. brachybotrys and the majority of American varieties twine in an anti-clockwise direction whilst W. floribunda and its hybrids twine clockwise.

Amongst those rated most highly by the assessors was W. sinensis ‘Amethyst, which had developed relatively little leaf at flowering time and so showed its flowers more effectively than many. Its scent was also stronger than others and it was also noted that unpruned shoots flowered later than pruned shoots to extend the flowering season.

W. sinensis ‘Prolific', noted as one of the most reliable, while W. brachybotrys was praised as the longest flowering of all and featured coppery young foliage.

Wisteria brachybotrys 'Showa-beni' at Witch Hazel Nursery. Image: ©Wendy Wesley/RHS Trials OfficeThe pink flowered W. floribunda ‘Hon-beni' seemed on course to retain the AGM it received in 1993 although the best pink for colour was considered to be W. brachybotrys 'Showa-beni' but this had not flowered well last year so, at present, is not considered to be of AGM standard.

Wisteria x formosa, a cross between W. floribunda ‘Alba' and W. sinensis raised in America more than a hundred years ago, was especially prolific.

Standard Wisteria x formosa on trial at Witch Hazel Nursery. Image: ©Wendy Wesley/RHS Trials OfficeOne interesting point. These wisteria are grown not as climbers but as standards, which keeps the flowers at a height at which they can be examined closely and their fragrance best appreciated. This is actually a way in which they should be grown more often, ideal for small gardens - as long as they're pruned regularly.



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