American Bellflower is a herbaceous biennial wildflower native to Eastern North America. Scientifically known as Campanula americanum, it grows 2-6′ tall in full sun and medium-moist, well-draining soil. Blooming a tall spike of showy blue to purple flowers for six weeks in Summer, it attracts numerous species of bees.
I. Appearance and Characteristics
Campanula americana, the American bellflower, or tall bellflower. Tall bellflowers can be annual or biennial with a varying life-history with seeds germinating in the fall producing annual plants and spring-germinating seeds producing biennial plants. Long-tongued bees are the primary pollinators, including Megachile campanulae, but halictid bees, butterflies, and skippers may also act as pollinators. Tall Bellflowers do not generally self-pollinate. Some authorities, including the USDA PLANTS database, consider the name Campanulastrum americanum to be the accepted name for this species.
Tall bellflowers grow from the Great Lakes region south to Florida and from the Dakotas east to New York. They thrive in partial shade and grow along woodland edges, in open woods, shaded meadows, streambanks and ditches.
A large central flower stem shoots up from a basal rosette, that terminates in a raceme 1/2-2′ long, with the plant’s overall height being 3-6′. The central stem is light green, slightly grooved, and hairy. The primary root system is a taproot. It has alternate leaves 3-6″ in length, that are lance-shaped to ovate-elliptic in shape, with rough/toothed edges.
Tall bellflower flowers are light blue to violet with a pale white ring at the throat, which primarily bloom in July and August. It is an unusual bellflower in that its flowers are flat. Flowers are approximately 1″ across. Its pistils have a recurved style and a three lobed anther and each flower has 5 stamen, 5 petals, and 5 sepals. The ovaries develop into 5 angled flat topped seed pods.
II. How to Grow and Care
Sunlight
While the American Bellflower is at home in a cooler environment, it does still enjoy full sun or partial shade. Because of this, make sure that your plant is placed in a location that receives some shade from the hot summer sun. If the American Bellflower is situated in the direct summer sun, then the flowers may start to wilt after just a couple of days.
Temperature
Native to northern temperate regions, the american Bellflower is suited to USDA hardiness zones 4-8. The plant thrives in temperatures around 16 to 18 ℃, and some varieties will survive cold temperatures down to -10 ℃. Although they prefer a cool summer, the american Bellflower can survive in temperatures up to 26 ℃, as long as they are regularly watered. If the temperature exceeds this, then the flowers will die, and the plant may not bloom again that year.
The american Bellflower is a flowering plant that adds a whimsical feel to many gardens across the world. Depending on the climate, it will generally bloom from the beginning of summer through to the first frost. While they are reasonably easy to care for, you will need to regularly check that they have enough water in order to prevent the delicate flowers from wilting.
Watering
The American Bellflower requires lots of water to produce its attractive, colorful, bell-like flowers. This is especially true in warm climates. If you do not water your plant regularly, then it will quickly wilt and stop producing flowers. Typically, the american Bellflower will need watering twice a week in warmer weather, but a good tip is to feel the soil before watering. It should be just slightly moist, but not water-logged or dry.
Soil
The optimum soil for your american Bellflower is fertile soil with a pH of 6-8, meaning neutral to alkaline. The soil must not dry too quickly, but should still be well-draining. Because of this, soils such as loam, sand, or clay are perfect for this plant. The american Bellflower does not like warm weather, so apply a layer of mulch to the soil in the summer. This will help to keep the soil and the roots of your plant cool and moist. The nutrients from the mulch will also encourage better growth and blooming.
Fertilizing
While it is not essential to use a fertilizer, many choose to apply an organic fertilizer to increase the quality, size and growth rate of the flowers. If you decide to use a fertilizer, apply it once or twice a month throughout the spring and the beginning of summer. Ideally, use a water-soluble fertilizer that you can apply directly to the soil. However, avoid getting any fertilizer on the american Bellflower, as this could burn the plant, and avoid nitrogen-heavy fertilizers too.
Planting Instructions
While many people choose to plant their american Bellflower in the garden, it will also happily survive when planted in an outdoor container. They are best planted in the fall, to give them enough time to establish their roots for the spring. These plants like to spread out, so be sure to plant them with enough room to do so, for example, a foot apart. Leaving this amount of space will allow for adequate air circulation around your plant, which can prevent powdery mildew.
When planting your american Bellflower, make sure that the hole is twice the size of the root ball and is about 38 cm deep, so that the tops of the roots are level with the soil surface. Then, fill the soil in and firm the top layer before watering. A good tip is to loosen the surrounding soil before planting to allow the plant to settle quicker. While the american Bellflower is occasionally kept indoors as a house plant, this is not recommended as the lack of light and dry air can quickly damage the plant.
Pruning
The typical american Bellflower will usually grow up to 1 m and reach an ultimate spread of 1 m. They are perennial, which means that they will bloom once a year. Because of this, they do not necessarily need pruning, unless you are trying to maintain a certain shape. The american Bellflower can take up to 5 years to reach its ultimate height, which is another reason why you may not need to prune your plant for quite a few years.
If you choose to prune for shape and to encourage growth, you should do this at the end of spring, and definitely before the beginning of fall. While pruning, remove any shoots that appear weak or are growing in the wrong direction. This will encourage the plant’s energy to be diverted towards the other shoots instead. During the flowering season, some choose to remove wilted flowers, as this can prolong the flowering phase. This can be done by ‘plucking’ off the dead flowers. Deadheading flowers will also prevent this plant from self-seeding.
Propagation
The american Bellflower can be propagated through division, planting seeds, or basal cuttings. Most choose division because the plant should be divided every five years anyway, in order to keep it growing strong and healthy, with propagating by division being easy to do. In the spring, dig up your american Bellflower and tease the roots apart. Then, gently cut the plant in half. Afterward, plant your american Bellflower in nutrient-rich soil immediately, lightly packing the soil around the plant before watering it. It is best to divide your american Bellflower on a cool day.
If you choose to plant seeds, simply sow them into nutrient-rich soil at the beginning of spring, after the last frost. Cover the ground with mulch to help the seeds germinate, and you should start to see shoots in the next 4-8 weeks. Be aware that the seeds for the american Bellflower are cold shooters, so they must be kept at a low temperature before planting to prevent them from driving out too early.
Transplanting
Spring, dubbed as S1, is the best season to transplant american Bellflower, this gives it adequate time to establish strong roots before winter. The plant thrives in part to full sun locations. Be gentle while transplanting to preserve its delicate roots, ensuring the successful growth of american Bellflower.
Overwintering
While many variants of the american Bellflower will not die in cold temperatures, frost can have a significant impact on the health of your plant. If planted in a container, many bring their bellflowers inside to a garage or shed during the winter season. If your plants are kept outside in the ground, consider covering your american Bellflower during hard frosts, especially if it is not yet mature.
Pests and Diseases
- Pests
Deer and rabbits will browse the foliage of American Bellflower.[3] I have personally seen the damage when rabbits mowed off the basal leaves of my plants. You should protect them with Liquid Fence until the stalks form.
- Disease
American Bellflower is generally not affected by disease, but can get various leaf fungi, although the damage is minorly cosmetic. However, the lower leaves will turn yellow and fall off during drought.
III. Uses and Benefits
American Bellflower is makes an impressive display when planted in clusters. Very showy, the tall spikes of blue to purple are eyecatching and really pop when contrasted against dark green backgrounds of a forest or taller plants.
Being able to grow and look great in many environments, there is certainly a place for American Bellflower in most home gardens.
The pollen and nectar produced by Tall Bellflower attract cores of bees when in bloom. Some butterflies and insects will be attracted for nectar while bees go for the pollen.
