The Award of Garden Merit (AGM) helps gardeners pick the best plants to grow at home. Here plantsman Graham Rice picks 10 of his favourite shrubs and climbers that have recently been awarded the AGM
The process of assessing plants and awarding the very best of them the Award of Garden Merit never stops. Either through trials at RHS Gardens, visits to comprehensive collections or discussions around the table, our teams of experts continually make recommendations which are then formally ratified by the Society’s plant committees. The coveted cup symbol can then appear on labels, in catalogues and online.
In recent years, a wide range of shrubs and woody climbers have received awards. Here is a selection of 10 of the best.
H1 - H7 indicated the new hardiness ratings
Full details of hardiness ratings (510kB pdf)
Upright and bushy, the foliage unfurls bright orange - quickly becoming lemon yellow with orange edges. The leaves remain yellow as the season progresses, until late summer when they develop greener tints, but retaining their orange edge. In autumn they turn gold before falling. Easier to grow than the similar ‘Katsura’ and keeps its yellow colour longer. Found in a nursery near Milan. 3m (10ft). H6.
The branches of this increasingly popular, multistemmed, easy-to-grow deciduous shrub carry 7cm (3in) lightly scented flowers through summer into early autumn. Each flower has about 20 wine red petals plus a few in the centre with white tips. The first hybrid between the American and the Chinese Calycanthus species, created by Richard Hartlage at the J. C. Raulston Arboretum in North Carolina. 3m (10ft). H5.
One of the earliest of its type to flower (sometimes blooming at Christmas), the gorgeous, creamy centred, pure white flowers are 7.5-10cm (3-4in) across and made up of a mass of petals, some reduced almost to stamens. The plants are neat and upright in growth and appreciate shelter and shade from the early morning sun to help prevent frost damage to the flowers. Grown since 1834. 2.5m (8ft). H5.
One of a number of excellent, recently introduced dogwoods grown for their colourful winter twigs, this form of our native species features winter stems which are yellow at the base grading to bright coral red towards the tips and deepening in colour as the winter progresses. More vigorous than most, it also features autumn foliage in yellow, orange and coral red. 1.2m (4ft). H6.
This unexpected member of the hydrangea family is a superb evergreen shrub for a sunny situation. In June and July the fragrant, pure white flowers, each with the cluster of golden anthers, open among glossy dark green leaves. ‘Elizabeth’ is noted for larger flowers carried in more generous clusters. Selected in California and named for the American botanist Elizabeth McClintock. 1.8m (6ft). H4.
The recent trial at RHS Garden Wisley of large flowered, late-flowering clematis highlighted some fine new introductions including Happy Birthday. With its velvety, dark purple, 10cm (4in) flowers maturing to cobalt blue, each featuring a contrasting cluster of white stamens in the centre and opening from June to September, the trial judges noted that the whole plant was covered in flower. 2.5m (8ft). H6.
Varieties of the oak-leaved hydrangea are increasingly recognised for the superb shrubs they are, and Snow Queen combines two fine features at different seasons. In August, upright cones of large white flowers open, developing pink tints as they mature. The flowers are followed by the foliage of the whole plant developing unusually long-lasting autumn colour in rich burgundy and coral red tones. 1.2m (4ft). H5.
From more than 30 entries in the recent trial of the ever-popular flowering currants, only four were awarded AGMs and ‘Koja’ stood out. In particular, the judges noted its neat and compact habit, not growing too large, and its prolific flowering. In March and April, long pendulous clusters of crimson flowers open with the unfurling foliage. The old favourite ‘Pulborough Scarlet’ had its AGM withdrawn. 1.8m (6ft). H6.
A culinary sage with foliage so good that it would be worth choosing simply as an ornamental foliage plant is clearly an attraction and ‘Berggarten’ is exactly that. The unusually broad foliage is an attractive silvery grey in colour, spikes of pale violet blue flowers open in summer and the plant is appealingly low and spreading. Good in containers and in gravel gardens. 60cm (2ft). H4.
One of the finest new shrubs of recent times, it combines leaves with the look of a cut-leaf maple and the toughness of an elder. The foliage is finely dissected and rich, dark purple – almost black – in colour and in June sets off large heads of pink flowers followed later by reddish-black berries. Can be pruned hard in spring to create an astonishing foliage plant. 3m (10ft). H6.