Edging Lobelia Lobelia erinus 'Cambridge Blue'

Water

To maintain healthy growth, Cambridge Blue lobelias should be watered regularly to ensure the soil remains evenly moist, but not waterlogged. During the growing season, typically in the spring and summer, water them thoroughly when the top inch of soil feels dry to the touch. Depending on weather conditions, this may mean watering once or twice a week. It's important to avoid overhead watering to reduce the risk of disease. Aim to provide about 1 gallon of water per square foot every week, adjusting for rainfall and temperature changes.

Light

Cambridge Blue lobelias thrive in bright, indirect light or partial shade. They perform best when they are protected from the intense afternoon sun, which can scorch their delicate foliage. A spot that receives morning sunlight with dappled shade in the afternoon is ideal. Avoid deep shade locations as this can lead to leggy plants and reduced flowering.

Temperature

Cambridge Blue lobelias prefer temperate conditions and perform best when the temperature is between 60 and 70 degrees Fahrenheit. They can tolerate minimum temperatures down to 50 degrees Fahrenheit at night and should not be exposed to conditions below freezing. During the summer, when temperatures are high, provide some afternoon shade to help cool the plants.

Pruning

Pruning of Cambridge Blue lobelias encourages bushier growth and more abundant blooms. Deadhead spent flowers regularly throughout the blooming season to promote continuous flowering. Pinch back stems in the early spring to stimulate branching. Light pruning can be done at any time during the growing season to maintain shape and vigor.

Cleaning

As needed

Soil

The ideal soil mix for growing Cambridge Blue Lobelia should be well-draining, moist, and fertile with a soil pH range of 5.5 to 6.5. A mixture comprising peat moss, perlite, and compost is suitable for optimal growth.

Repotting

Cambridge Blue Lobelia should be repotted annually in the spring as it is generally treated as an annual plant. If grown as a perennial in suitable climates, repot every 2 to 3 years to refresh the soil.

Humidity & Misting

Cambridge Blue Lobelia prefers moderate to high humidity levels but is relatively tolerant and can thrive in average room humidity.

Suitable locations

• Indoor

  Ensure bright, indirect light and moist soil for indoor Cambridge Blue Lobelia.

• Outdoor

  Place in partial sun to full sun and keep soil consistently moist outdoors.

• Hardiness zone

  10-11 USDA

Life cycle

Lobelia erinus 'Cambridge Blue', commonly known as the Cambridge Blue lobelia, begins its life cycle as a seed, typically sown in late winter or early spring under cover or directly into warm soil after the last frost. Upon germination, the seedlings grow into young plants, developing a compact, branching habit with delicate foliage. As the temperature rises, the lobelia enters the vegetative growth stage, focusing energy on producing more leaves and stems. Flowering ensues in late spring or early summer, with the plant producing numerous small, striking blue flowers that can last until the first frost in autumn. After flowering, the lobelia sets seed, dispersing them to create new plants, or the plant may be prompted to produce a second bloom if the spent flowers are removed. In colder climates, Lobelia erinus is treated as an annual, completing its life cycle within one growing season, while in milder regions it may survive as a perennial through a period of dormancy over the winter before resuming growth in the spring.

Propogation

• Propogation time

  Spring-Early Summer

• Propogation: Lobelia erinus 'Cambridge Blue', commonly known as Lobelia, is most effectively propagated through seed. The best time for sowing Lobelia seeds is in late winter to early spring, about 10 to 12 weeks before the last frost date. Sow the tiny seeds on the surface of a well-draining seed starting mix, gently pressing them into the soil as they need light to germinate. Keep the soil consistently moist but not waterlogged, and maintain a temperature between 70 to 75 degrees Fahrenheit (21 to 24 degrees Celsius). Germination usually occurs within 14 to 21 days. Once the seedlings have developed their second set of true leaves and are sturdy enough to handle, they can be transplanted into individual pots before eventually being moved to their final location outdoors after the threat of frost has passed.