Purple flowering plant,Campanula portenschlagiana, commonly known as Bellflowers, growing in the corner of an ancient doorway in Northern France Stock Photo - Alamy
Wall bellflower - info, planting, care and tips - live-native.com
Bellflower (Campanula portenschlagiana 'Royal Blue') in the Bellflowers Database - Garden.org
Campanula portenschlagiana - Wikipedia
Photo Campanula portenschlagiana 'Royal' | Global Flowers