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All ratings refer to the UK growing conditions unless otherwise stated. Minimum
temperature ranges (in degrees C) are shown in brackets
AGM plants have been through a rigorous trial and assessment programme. They are:
This plant will provide nectar and pollen for bees and the many other types of pollinating insects.
It is included in an evolving list of plants carefully researched and chosen by RHS experts. Divided into 3 groups these lists, linked below, are maintained by a team of RHS staff and are reviewed annually.
'Roy Davidson' is a clump-forming perennial to 1.1m, the stems with 10 flowers or more, light yellow with light brown veining, the falls with a crescent-shaped brown central flash
I. pseudacorus is a vigorous herbaceous perennial forming extensive colonies to 1.5m in height, with bright yellow flowers up to 10cm in width, the falls with brown veining in the centre, in mid and late summer
'Variegata' is a vigorous herbaceous perennial forming extensive colonies to 1.5m in height, with long erect leaves striped yellowish-white. Flowers up to 10cm in width, yellow, the falls with brown veins in the centre
'Regal Surprise' is a deciduous perennial, a hybrid of I. pseudacorus and I. versicolor, that flowers in early summer, violet-purple and white with a yellow signal on the falls
Last-listed in the RHS Plant Finder in 2002
This plant is listed in the RHS Plant Finder book. At present our information about this plant is limited to a list of the nurseries that supply it. In time we will be adding more details including a description, growing information, advice and photographs.
Over 70,000 plants and where to buy them
Britain’s best gardening annual, available now from RHS Mail Order and all good bookshops.
Listed in the RHS Plant Finder
Last-listed in the RHS Plant Finder in 2011
Last-listed in the RHS Plant Finder in 2010
Last-listed in the RHS Plant Finder in 2013
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