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Graham Rice on Trials

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

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  • Dark-leaved dahlias

    Graham Rice on 30 Dec 2009 at 03:04 PM

    Dahlia 'Twyning's Revel' - dark leaved dahlia. Image © Do not reproduce without permission.For so long it was the flamboyance of the flowers that was the attraction of dahlias and no one paid any attention to the leaves. These days we take it for granted that many of the best garden dahlias don't have boring green leaves - they have luscious bronze or purplish foliage which is a feature in itself.

    First ‘Bishop of Llandaff' caught gardeners' imagination and also ‘Yellowhammer' came along. Seed strains like ‘Redskin' appeared in catalogues, and the double orange  ‘David Howard' appeared at Great Dixter and other gardens.

    Now dark-leaved dahlias are taken for granted. Quite a number, large and small, have been seen in the Wisley trial in recent years and least two breeders, Aad Verwer in Holland and Keith Hammett in New Zealand, have devoted time to them.

    In this year's trial, as you'd expect - some did well, some not so well. None from the Dutch Happy Single (HS) series, raised by Aad Verwer in The Netherlands,  have yet been given an AGM but ‘Happy Single Kiss', salmon with a dark centre, ‘Happy Single Date', deep orange with a dark centre, and ‘Happy Single Wink', lilac with a purple centre, have come close.

    ‘Keith's Pet', from Keith Hammett, was given an AGM as a container plant but, though good, was less effective in the open ground. a star at Hampton Court in 2008 and another from Keith Hammett, with petals striped in lavender pink and white. These must be prime candidates for awards next year.

    Two others came close this year and will be examined again next year. ‘Twyning’s Revel’ (top) in soft coral red with a yellow centre and the gorgeous Dahlia 'Candy Eyes' - dark leaved dahlia. Image © Do not reproduce without permission.‘Candy Eyes (left)’, a star at Hampton Court in 2008 and another from Keith Hammett, with petals striped in lavender pink and white. These must be prime candidates for awards next year.

  • Award winning parsnips

    Graham Rice on 23 Dec 2009 at 12:02 PM

    Parsnip 'Albion' - Award of Garden Merit at the Wisley trialAs a staple of Christmas Dinner, this seemed a good moment to take a look at the awards that came out of  this year's parsnip trial at Wisley. Twenty one different varieties were grown, from old and familiar names like ‘Tender and True' to the very latest F1 hybrids. Ten were given Awards of Garden Merit (AGM).

    Seed was sown on 21 April at 2.5cm/1in intervals in rows 16in/40cm apart. And here's a crucial part of the growing regime: the whole crop was covered with Enviromesh as protection against root fly. It was briefly removed for thinning the seedlings to 3in/7.5cm in June, again once for weeding, and finally removed in September. The result: it proved very successful in keeping off the root fly.Enviromesh covering parsnips, protection against root fly. Image ©

    By the end of September the crop was ready to harvest although most gardeners will leave their parsnips in the ground and use them as needed. They will continue to bulk up in to the autumn.

    Almost half the entries were given AGMs, a testament to the progress in breeding parsnips in recent years. New award winners were: ‘Albion' (above): a uniform crop of unusually white, smooth-skinned roots; ‘Archer': good for the village Parsnip 'Lancer' - Award of Garden Merit at the Wisley trialshow as well as the table; ‘Lancer' (left): short, slender roots, ideal for baby-root crops; ‘Palace': good quality roots, with canker resistance; ‘Panache': very evenly tapered roots with smooth skins; ‘Picador': less tapered than many, so with more bulk per root.

    Four varieties which received the AGM in 1993 or 2001 were still considered good enough to retain their award. ‘Cobham Improved Marrow': elegant tapering roots and canker resistant; ‘Dagger': smooth roots with a shallow crown mean easy cleaning; ‘Gladiator'; the first F1 hybrid still has star quality; ‘Javelin'; another easy-to-wash variety with canker resistance.

    Finally, amongst those no longer considered of Award of Garden Merit standard was ‘Tender and True'. The expert panel of assessors considered that this was now outclassed, having been superseded by more modern varieties, but that it continued to sell well because of its appealing name.

    It's also worth noting that all the top varieties are F1 hybrids except ‘Cobham Improved Marrow' and ‘Lancer'. However, unlike many crops, the price difference between open-pollinated and F1 Hybrid varieties is relatively small so seed price need not be a serious factor in choosing varieties.

    Hoping you're enjoying home-grown Christmas parsnips. If not, you know which varieties to try for next year.


  • Superb spuria irises

    Graham Rice on 16 Dec 2009 at 02:24 PM

    Iris 'Hickory Leaves' - Award of Garden Merit. Image: ©RHSAmongst the many thousands of summer Iris cultivars, it's usually the flamboyant bearded irises that get most of the attention. But the recent trial of Spuria irises again proved what valuable perennials they are.

    Spuria irises are tall, up to around 1.5m/5ft, and while the flowers lack the rainbow colours and patterns of the Tall Bearded Irises their colours can be intensely penetrating in colour. They also have a more imposing habit than bearded irises, their slender deep green foliage setting off the flowers well


  • Buddleja – visitor voting and butterfly count

    Graham Rice on 10 Dec 2009 at 04:39 PM

    Buddleja 'Miss Ruby' - the most popular buddleia with visitors. Image: ©ProvenWinners.comThe figures have just become available for both the visitor voting and the butterfly count for the big buddleja trial at Wisley. Visitors were again asked to nominate their favourites and a count was also made of the number and type of butterflies visiting each variety.

    The visitor voting results were both very similar and very different to last year. In 2008 the top two varieties were ‘Miss Ruby', way out ahead, followed by Lo and Behold 'Blue Chip'. I wrote the results up on my Transatlantic Plantsman blog.

    This year top of the poll is again the vivid and prolific ‘Miss Ruby' but ‘Blue Chip' was way way down with less than 1% of the vote. ‘Blue Chip' was indeed good in its first year but in its second, when I saw it in mid July, it was very disappointing without a single flower open while many others looked spectacular.

    So ‘Miss Ruby' was again way out ahead with twice as many votes as the next placed ‘Raspberry Wine' and ‘Purple Prince' followed by ‘Burgundy' and ‘Santana'.

    Buddleja 'Orchid Beauty' - the most popular buddleia with butterflies. Image: © Read More...

  • The sweetest sweet corn

    Graham Rice on 02 Dec 2009 at 01:14 PM

    Sweet corn 'Seville' - one of the stars of the Wisley trial. Image: ©Victorian Garden NurseryAround the world sweet corn is such an important crop that plant breeders are constantly introducing new varieties. Many were on show in this summer's Wisley trial and an interesting feature was how existing AGM winners frtom previous trials have been outclassed by recent introductions.

    One of the stars of the trial was the supersweet variety ‘Seville' (left), described by the judging panel of vegetable experts as having "attractive, later maturing cobs with good shape and straight rows of small grains." Another independent assessment, from Stephen Shirley of Victorian Nursery Garden, confirms this view: "Seville is a fantastic variety of. Grows huge (as a plant), crops well with big cobs (3 per plant is about normal), has a good flavour and is hardy and easy to grow in cold years."

    Sweet corn 'Mirai White' - one of the sweetest in the Wisley sweet corn trial. Image: ©Thompson & MorganTrialled for the first time this year were four of a new type, the Mirai Series. These were all very early but also distinct in having very thin skins to the individual kernels. The panel noted that all four varieties were exceptionally sweet and tasty and that the eating experience was also enhanced by the thin skins. However, the thin skins also laid them open to disease infection and it was suggested that seed be sown in pots and young plants set out rather than sown direct into the soil.

    Only two of the Mirai Series are available at present. ‘Mirai Bicolour' was described by the judging panel as: "Very tender, with exceptional flavour.  Large, sweet, well-filled cobs." ‘Mirai White' (above) was described as having "Attractive white cobs... exceptionally tender and sweet... very good flavour."

    Others to perform especially well this year included ‘Conqueror',  ‘Lapwing', ‘Marshalls Honeydew' and ‘Sparrow' along with these varieties which already have an AGM following the last trial: ‘Earlibird', ‘Lark', ‘Northern Xtra Sweet', ‘Ovation', ‘Prelude' and ‘Swift'.

    And finally, those varieties which had previously been awarded an AGM - some as long ago as 1996, an eternity in sweet corn development - but which have now been superseded or which are not now available having been outclassed: ‘Dickson', ‘Dynasty', ‘Gilden Giant', ‘Golden Sweet', ‘Gourmet', ‘Mainstay' and  ‘Start Up'.

    Look out for these top performing varieties when ordering seed for next year. I'll let you know when the ratified AGM awards become available.