Planting a Bellflower from Seeds

Bellflower seeds are readily available and easy to sow for color, shape and contrast in the home garden. Although there are some biennial and annual versions, most bellflowers (campanula) are perennials. With more than 300 varieties to choose from, there’s one for every home garden design consideration. Here's what you need to know to plant bellflowers in the landscape.

Overview of Bellflowers

Its botanical name is Campanula, and bellflowers are a hallmark of a cottage garden, as well as mass borders, rock gardens and specimen plantings. Some are diminutive in size, ranging 4 to 6 inches tall and about 8 inches wide. Others are more in the mid-range size - about 18 to 24 inches tall, while some are giants reaching more than 3 feet in height. Some prefer part shade, while others, particularly in cooler northern climates, can tolerate full sun.

The plant’s common name, bellflower, is appropriate for the bell-shaped blooms with striking petals. Most varieties bloom from about mid-summer to first frost (although some can take a light frost). They’re also free from the usual garden pests and diseases, but do keep them well watered.

Starting Bellflower Seeds

Even for the novice gardener, starting bellflower seeds is quite easy. Most prefer to sow the seeds directly outside as soon as temperatures are consistently warm, usually in late spring. Bellflower seeds may also be sown indoors in flats with a seed compost and sprinkled with vermiculite and then transplanted outside later. Be sure to allow sufficient time for the seeds to germinate and match up growing time with outside weather temperatures.

For outdoor planting, sow seeds spaced 12 to 18 inches apart (depending on mature height for variety). Cover lightly with about 1/8-inch of soil.

Germinating bellflower seeds will take about 14 to 21 days. Be sure seedlings have enough light and keep them sufficiently watered, especially during the first growing season.

Some varieties of bellflower seeds, such as clustered bellflower and Serbian bellflower, are sown in late spring, summer or early autumn, for flowering the following spring. This is because they require cold for germination. Read the seed packet or instructions from the bellflower seeds source.

Thin Out Bellflower Seeds as Necessary

Again, depending on variety of bellflower seeds, some are so tiny it’s impossible to space them adequately when sowing. In that case, or if planted seeds grow too close together, thin them out once they’ve reached a size large enough to handle. Always keep in mind the overall dimensions of the plant at maturity (height and width). For mass plantings and borders, it’s okay to have low-spreading bellflowers closer together. But for specimen plants, be sure to give them the room they need.

Deadhead to Keep Healthy

As with most perennial flowers, deadheading bellflowers will keep them healthy and encourage more prolific blooms. Deadheading is best done while weeding and cultivating around the plant. Do this in the early morning and it will be less stressful to the plant.