Words: Graham Rice
Roscoeas are hardy perennials which are especially valuable because they are colourful shade-lovers which flower in the summer when so many shade-loving flowering perennials are long past their best.
So, as more forms have been introduced in recent years and to select the best for most gardeners, in 2008 the RHS began a trial. The trial ended last year and out of more than 100 entries fourteen received the Award of Garden Merit.
One of those with which gardeners will be most familiar, and which received the AGM, is Roscoea auriculata. Nine different plants of R. auriculata were grown and the panel of experts assessing the trial felt that they were all so good that the species as a whole was worthy of the AGM. 'The variation between these plants was small and within the group there were no poor plants,' they reported, adding that they were 'good value plants that are vigorous and produce plenty of flowers over a long period.'
Reaching about 38cm (15in) in height, the heavily corrugated foliage supports bright flowers with bold purple lips and a slightly paler hood. The flowering season of all the plants was recorded and R. auriculata bloomed from about the 7 July well into September though as temperatures dropped in the autumn, the number of flowers was much reduced.
One selection of R. auriculata, ‘Summer Deep Purple’ was also given the AGM. The assessment panel summarised their thoughts about the plant: 'Lots of lush growth and tall for an R. auriculata. Vigorous and bulks up quickly and could need fairly regular division, or the plant can keel over when it gets overcrowded. Produced a lot of flower over a long period. A great garden plant.'