Campanula alpina (sometimes called Campanula caespitosa) is a species of campanula native to the European Alps. Often simply called the "alpine bellflower" for its bell-shaped blooms, this cold-hardy species is found clinging to rocky cliffs in the wild and is an excellent choice for rock gardens, according to Sue Wooster, Plant Heritage certified national plant collection holder of alpine campanulas. These hardy perennials require only basic culture once established, Wooster says, and will easily reseed themselves year after year with proper care.
Choose a location for your Campanula alpina that is either in full sunlight or partial shade. Morning sunlight followed by afternoon shade is best for warm climates. This plant is cold-hardy to USDA growing zone 2.
Amend very wet soil with sand and peat moss to aid in drainage. These plants thrive in gritty, low-nutrient soil but do not do well in wet soil or soil that collects standing water.
Plant seedlings about 12 inches apart in late winter or early spring. Or scatter seeds on the soil and cover with a very thin layer of dirt. Exposure to frost aids in germination, Wooster says.
Keep the soil moist until seeds germinate. If planting seedlings, keep the soil moist for the first month, then let it dry out between each watering. Alpine campanulas have deep taproots that allow them to tolerate periods of drought.
Deadhead the flowers (trim off the blooms) after they are spent to encourage a second flowering.
Propagate by division in the spring when the ground has thawed.