Botanical Name: Lobelia erinus ‘Rift Purple’

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: Rich Purple Blooms with White Accents, Dense Flower Coverage, Excellent Color Saturation

Uses: Containers, Hanging Baskets, Window Boxes, Borders, Cool-Season Color

Patent: ❌ Not Patented

Propagation: ✔ Propagation Allowed

See our complete Lobelia Plant Guide for more in depth care details.

More About Lobelia ‘Rift Purple’

Lobelia ‘Rift Purple’ produces a deep, saturated purple bloom that feels richer and more dramatic than the softer blues most people associate with Lobelia. When the plant is in full flower, the blooms gather tightly over the foliage and create a thick layer of color that almost hides the leaves beneath it. From a few steps away it reads as one solid mass of purple, which makes it incredibly effective in containers where you want color that feels bold but still refined.

The plant naturally grows with a nice balance. The center fills in densely while the outer stems loosen slightly and spill outward, which gives containers a fuller, more natural look. It never feels wild or floppy, just relaxed enough to soften the edge of a pot or window box. I’ve also noticed it works especially well in containers where the other plants have different textures. The small flowers and fine foliage create a soft layer that contrasts nicely with broader leaves like calibrachoa or trailing foliage plants.

Why We Like It (Our Trials)

In our trials here in the Upstate, ‘Rift Purple’ really shines in early Spring when temperatures are still cool and the garden is just waking up. It tends to settle in quickly and start producing flowers almost immediately, which makes containers look established far sooner than you might expect. One thing we’ve noticed over the years is how evenly the plants tend to grow. Some lobelias can get patchy as the season moves along, but ‘Rift Purple’ usually fills in across the whole plant, keeping that dense cushion of blooms intact for much longer. 

I also like the way this color behaves in container design. Purple has a way of grounding a planting and giving it depth. When you combine ‘Rift Purple’ with whites, pale yellows, soft blues, or silver foliage, the purple adds just enough contrast to make the whole container feel more layered and interesting. It’s the kind of plant that doesn’t scream for attention on its own, but once you see it in a finished container you realize how much it’s doing to hold the entire planting together.

Rift Purple vs. Other Lobelia Varieties

Rift Purple shares the same trailing habit as Rift Blue but introduces a deeper, warmer hue that adds richness to container designs. It flows over edges with the same refined movement, yet its color gives it more depth than blue selections. This makes it especially useful when blending purples, pinks, and soft pastels in spring containers.

When compared to Hot® Purple, Rift Purple is noticeably more subdued and easier to balance with other plants. It also contrasts with Techno® Dark Blue and Magadi™ Compact Blue Bay, trading uniform structure for organic movement. Gardeners often choose Rift Purple when they want trailing Lobelia that enhances a design without dominating it.