Botanical Name: Lobelia erinus ‘Rift Blue’ Common Name: Annual Lobelia Hardiness Zone: Grown as an Annual in All Climates Size: 6–10" Tall × 12–18" Spread Growth Habit: Mounding to Lightly Trailing Habit Sunlight: Full Sun to Partial Shade (Best Performance in Morning Sun / Afternoon Shade) Soil: Well-Drained, Moisture-Retentive Soil Water Needs: Moderate; Prefers Consistent Moisture Bloom Season: Spring through Early Summer (May Persist Longer in Mild Weather) Fertilizer: Light, Regular Feeding for Best Flowering Features: Intense Deep Blue Blooms, Excellent Color Saturation, Dense Flower Coverage Uses: Containers, Hanging Baskets, Window Boxes, Borders, Cool-Season Color

Patent: ❌ Not Patented Propagation: ✔ Propagation Allowed

More About Lobelia ‘Rift Blue’

Lobelia ‘Rift Blue’ is valued for its exceptionally deep, saturated blue flowers, offering one of the richest blue tones available in annual lobelia. The blooms form a dense blanket of color over the foliage, creating strong visual impact in containers and mixed plantings.

The plant maintains a balanced habit—mounding in the center with gentle trailing at the edges—making it versatile for both upright containers and cascading applications.

Why We Like It (Our Trials)

In our trials, ‘Rift Blue’ has performed especially well in spring plantings and cooler temperatures, delivering heavy bloom early in the season. With consistent moisture, it remains compact and floriferous without thinning or stretching.

We especially appreciate its color depth. The rich blue pairs beautifully with whites, yellows, soft pinks, and silver foliage, and it adds contrast that lighter blue lobelias can’t always achieve.

Rift Blue vs. Other Lobelia Varieties

Rift Blue is selected for its graceful trailing habit, making it one of the strongest spiller options among annual Lobelias. While Magadi™ Compact Blue Bay and the Techno® series focus on structure, Rift Blue emphasizes movement, flowing naturally over container edges and window boxes. Its cool blue tone is classic and easy to pair with whites, yellows, and silver foliage.

Compared to Rift Purple, Rift Blue feels cleaner and more traditional in color, while Rift Purple adds warmth and depth. Against Hot® Purple, Rift Blue is far more restrained and easier to integrate into complex designs. From a gardener’s standpoint, Rift Blue is the go-to choice when softness and cascade are the priority.