Campanulas are also referred to as bellflowers, and there are annual, perennial and biennial varieties. Some species are indigenous to the United States (such as Campanula scouleri), and some are native to different parts of Europe (such as Campanula persicifolia). Of the more than 300 varieties, most thrive in zones 1 through 7. The blossoms are usually bell-shaped, but some varieties are shaped like a cup or star, and can also be round or flat, with colors that include purple, blue, white or pink.
Planting Campanula Seeds
Place seed starting mix into your planting cells eight to 10 weeks before spring. Water each until the soil is saturated.
Sprinkle three to four campanula seeds into each planting cell. Cover the seeds with no more than 1/16 of the seed starting mix. Mist the surface of each planting cell.
Place the cells in a sunny, warm environment (65 to 70 degrees F). Keep the seeds moist by spritzing them with water once the soil in the planting cells starts to appear dry. Germination time varies, but in two to three weeks, you should see sprouts.
Some varieties will not bloom the first year of growth. Once your seedlings grow to 3 to 4 inches in height, decide if you wish to plant your campanulas into your garden, or put them in larger pots for transplanting into your garden in the fall.
Choose a spot in your garden best suited to these plants. The majority of campanulas require well-draining soil and full sun (though some species can tolerate partial shade).
Turn over the soil to a depth of 4 to 5 inches and amend it with 1 to 2 inches of compost or other organic material. Smooth out the area with your rake and water the soil until it's well moistened but not soggy. To plant your campanulas into a bigger pot, or into a hanging basket, fill up your planting receptacle with a good quality potting mix. Let water run through the pot until it begins to come out its drain holes.
Dig holes twice the diameter and width of each planting cell. Spacing should be set at approximately 7 inches apart for smaller varieties 15 inches apart for larger ones.
Gently extract a seedling from a planting cell either by pushing up from the button with your thumb, or carefully cutting way the plastic with a garden knife or shears.
Put the campanula seedling into the hole, making sure it sits level and even with the surrounding soil; otherwise, place more dirt in the hole until the seedling sits level. Hold the seedling firmly and push in soil around it, patting it as you go.
Water each of your campanula seedlings using a gentle, slow stream of water. Don't saturate the tender seedling.