How to Grow and Care for Cathedral Bells Plant

Cathedral Bells, or Cobaea scandens, is a vigorous, fast-growing climbing plant with distinctive flowers. Also called cup and saucer vine, this plant originates from Mexico and features large, bell-shaped flowers that rest upon a green, saucer-like calyx. The blooms begin as a pale green and mature into a rich purple, releasing a floral-honey fragrance. Its lush foliage provides a dense screen, making it a popular choice for covering structures.

Planting Cathedral Bells

Starting Cathedral Bells from seed indoors is the most common way to ensure flowers during the first year. The large, tough seeds benefit from preparation to speed up germination; soaking them in water overnight is helpful. Sow seeds six to eight weeks before the final spring frost. Plant each seed individually in a pot filled with a standard potting mix, placing it with its longest edge pointing down into the soil to aid sprouting.

Germination can be erratic, but sprouts appear within two to four weeks if the soil is kept warm, between 70 and 75 degrees Fahrenheit. Once the seedlings are established and all danger of frost has passed, they can be transplanted outdoors. When transplanting, handle them gently to avoid damaging the root system. Choose a location that will accommodate their sprawling nature.

Directly sowing seeds into the garden is an alternative, though this method often results in a delayed blooming period. If doing so, wait until the soil has warmed and there is no risk of frost.

Cathedral Bells Care Guide

Cathedral Bells requires full sun for prolific blooming, meaning at least six to eight hours of direct sunlight daily. In climates with intense summer heat, a position that offers some light afternoon shade can be beneficial, but ample sun is needed for flowering. A spot that is too shady will result in lush foliage but few to no blooms.

This vine thrives in well-draining soil that is rich in organic matter. Good drainage prevents root rot, though the plant is not particular about soil pH. Amending the soil with compost will fuel its rapid growth. The soil should be kept consistently moist, especially during hot and dry periods, but avoid letting it become waterlogged.

As a vigorous climber, providing a sturdy support structure is fundamental. A trellis, arbor, or fence allows the vine to climb using its tendrils to secure itself. This support should be in place at planting, as the vine will need something to grasp early on. Without a structure to climb, the plant will spread across the ground.

Cathedral Bells is a tender perennial grown as an annual in most regions. It is reliably perennial only in USDA hardiness zones 9 through 11, where it may remain evergreen if the winter is mild. In colder climates, potted specimens can be brought indoors for the winter. To survive, they need to be kept in a bright location where temperatures stay around 45°F (7°C).

Pruning and Maintenance

Regular pruning helps manage the vine’s size and encourages a fuller appearance. You can pinch off the growing tips once the stems have reached the top of their support structure. This prompts the plant to develop more lateral branches, leading to more flowers. Throughout the season, remove any dead or damaged foliage.

A consistent fertilizing schedule supports the plant’s growth and flowering. Use a balanced, all-purpose liquid fertilizer every two to four weeks during the growing season. Be cautious not to over-fertilize, particularly with high-nitrogen formulas. An excess of nitrogen can stimulate dense foliage growth at the expense of flower production.

Propagating Cathedral Bells

Propagating Cathedral Bells is done using softwood cuttings. The best time to take cuttings is during the growing season in late spring or early summer. Select a healthy, non-flowering stem and take a cutting that is several inches long and includes at least two nodes (the points on the stem where leaves emerge).

Prepare the cutting by removing the leaves from the lower portion of the stem. Place the cutting in a glass of water or a pot with moist potting soil. If rooting in soil, a humid environment encourages root development. Roots should begin to form within a few weeks, after which the new plant can be potted up.