• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Blast-off for a brilliant new cosmos

A new British-bred cosmos was the star of this year's display of more than 80 varieties on the Wisley trials field

One of the most colourful, and interesting, features at RHS Garden at Wisley this year was the display on the trials field of more than 80 different cosmos, marking 2016 as The Year of The Cosmos.

Cosmos 'Apollo White'I was delighted to be included in the panel assessing them for Awards of Garden Merit and I’ve looked them over four or five times this summer. One of the most striking aspects of the trial was how some of the old favourites had declined and how good some of the newer introductions are.

The Sonata Series, for example, has been recognised as the best of the shorter kinds for decades but, frankly, it’s not what it was: it’s become variable in height, some of the flowers are very starry in shape and I’ve noticed that occasional flowers in the wrong colour turn up. Some other old favourites, including ‘Purity’, were very late; others, including ‘Psyche’, were very leafy with few flowers.

But new on the market this year is the British-bred Apollo Series, in carmine, pale rose pink and white. All three colours have been exceptional in the trial. Reaching about 60cm (2ft) in height, and very even in growth, the 4cm (1½in) flowers are consistently full and broad-petalled and with none of the off-type in the plants I’ve seen in other varieties.

Another good newcomer for the coming season is ‘Rosetta’, a little taller at 70-90cm (28-35in), with lovely pink and white softly striped semi-double flowers.

Cosmos ‘Apollo White’ is available as seed from Dobies, while ‘Apollo Mixed’ is available as seed from Nicky’s Nursery and as plants from Jersey Plants Direct. Cosmos ‘Rosetta’ is available from Johnsons.

*Please note the contents of this blog reflect the views of its author, which are not necessarily those of the RHS

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