Clear weeds from an area in full sunlight and moist well-drained soil. If you live in a climate with hot summers, plant purple campanula where the plant will be in the shade during the afternoons. Loosen the soil with a shovel and dig a hole to plant the campanula to the same depth it was in its nursery pot.
Water purple campanula regularly and keep the soil evenly moist. Don't allow the soil to become either soggy or bone dry.
Remove spent blooms to keep the plant blooming as long as possible. Cut the blooms for cut flower bouquets as often as you like.
Cut the purple campanula plant down to the lowest sets of leaves with pruners in autumn when the plant is finished blooming and the foliage begins to look straggly.