I love Campanula, which are sometimes called bellflowers. They belong to the Campanulaceae family and are one of the quintessential English cottage garden plants. Not many of them do well in Sydney's climate, unfortunately. I grew this species, sometimes known as rampion, from seed many years ago, and it had remained in my garden ever since. It has a basal clump of foliage and sends up tall spires of lovely purple/blue flowers (ht 30-40 cm): most prolifically in spring but also at other times of the year. It spreads to form a clump and gently self-seeds. It looks quite similar to Campanula rapunculoides, which is supposed to be a terrible spreader; I have never been able to grow that one at all and my one is not rampageous.
It likes to grow in a sunny, well-drained spot with reasonable soil. It can be divided up for purposes of propagation: the roots are thick and fleshy.
I have read that these roots, and the leaves, are edible and were craved by Rapunzul's mother when she was pregnant, in the Grimm Brothers' fairy tale: hence the species name. In the story, the plant was called 'rapunzel'. However, I have never tried to eat them!
I would never want to be without this plant. I live in hope that one day a seedling will come up with white flowers, which would be a beautiful sight.