Buddleia ARGUS® Velvet is a butterfly bush with beautiful violet flowers. It has been modified to not produce seeds thereby controlling its spread. It is recommended to prune the plant each year & can be done up to knee-height yearly in spring time after the last of the snow which will force the left over dormant buds from the previous summer to produce new shoots. Flowers July-September. Height 150-200cm. Supplied in a 3 litre pot.