Buddlieja alternifolia ‘Unique’
This is a dwarf selection of this attractive but rather large shrub. It is an ideal plant for a large patio container – good in a sunny place and is best pruned hard every year in March. .’Unique’ makes a compact plant, no more than 1m (3ft) tall, its prolific clusters of lilac-purple flowers opening for a long season from June to October against attractive silvery green foliage.
The flowers are delightfully fragrant, but produce no pollen and this greatly reduces the possibility of annoying seedlings popping up everywhere. It does, however, produce nectar so is attractive to butterflies. Image thanks to RHS