Campanula medium is a cheery biennial species that can be grown as a hardy annual in most climates. Planted in the fall, they will reward you with tall stems in the late spring covered in bright and cheery bell-shaped blooms, hence the common name Canterbury Bells. These plants are often seen in cottage-style gardens and are a robust and long-lived cut flower in the vase, however they are typically not available as young plants from nurseries due to the specific timing they must be planted for the healthiest plants and best quality flowers.

When these plugs are received, it’s important to harden them off to the elements for a few days prior to planting in your garden, especially if the weather is particularly hot and sunny. Keep the plants well watered during this time and gradually expose them to full sun over the course of a few days before planting out. Plant them into an area in your garden with rich, well-drained soil. Consider adding some compost and slow-release fertilizer at the time of planting to give the plugs the nutrition they need to reach their full potential. The key aspect to achieving success with Campanula medium is to plant them during *short* day lengths. This means 12 hours of daylight or less (ideally less). We suggest fall planting no earlier than the end of September for this reason – and they can successfully be planted through the winter in southern zones (USDA hardiness zones 6-10) and into very early spring in northern zones (USDA hardiness zones 4-5). While your plants are actively growing it’s also wise to water them with water-soluble fertilizer to provide adequate nutrients as the plants prepare to flower; if your winters are cold and the plants are dormant there is no need to fertilize, simply make sure the soil remains damp. A balanced fertilizer, or one specifically designed for flowering annual plants will work well.

We suggest planting these plugs at minimum 6 inches apart. If you have more space, they will be happy with more space. Fall-planted campanula plugs will get larger and take up more space compared to spring-planted plugs. When grown in optimal conditions, these plants can easily reach 3-4 feet in height in late spring, but don’t be alarmed if yours max out at around 24 inches in height. Campanula medium are obligate long-day plants, meaning flower buds are initiated when the daylengths exceed 12 hours regardless of when the plugs are planted. Planting in the fall allows the plants many months to grow vegetatively before flower buds are initiated, but planting in the spring only gives the plants 1-2 months to grow a rosette of leaves and a hearty root structure before sending up flower stalks. We typically do not pinch campanula and expect to see one large main shoot with several smaller side shoots. If you wish, you can pinch the central stem out from the plants when they are a few inches tall and this will encourage more vigorous side branching – the outcome will be more branches, but overall, they will be shorter. Tall plants will likely require some form of staking, especially when the plants are in full bloom and top-heavy. Monitor plants closely for typical plant pests – aphids and thrips will likely be your biggest enemies, but campanula are typically quite disease and pest resistant (even deer and rabbit resistant, but don’t be fooled by that description – they will still be nibbled on if deer or rabbits are very prevalent in your area and other food sources are scarce).

If you choose to cut some stems to enjoy in your home, we suggest cutting when most flowers are still in bud and only the first bud or two have opened; this will help maximize vase life and keep your arrangement looking perky for a longer period as buds continue to open. Use fresh water and recut the stems regularly (every couple of days should be fine) – the use of a floral food can also help increase vase life. If kept out of the sun and in a relatively cool space, campanula can last up to two weeks in a vase. These plants deserve a spot in everyone’s garden but heed this warning: if campanula medium are planted at the incorrect time for your zone – if the days are already longer than 12 hours, the plugs will immediately enter their bloom cycle and each plant will produce one or two flowers on measly 3-inch stems. Follow our advice closely for best results.