Botanical Name: Lobelia cardinalis

Common Name: Cardinal Flower

Hardiness Zone: Perennial in USDA Zones 4–9

Size: 24–48" Tall × 18–24" Spread

Growth Habit: Upright, Clump-Forming Perennial

Sunlight: Full Sun to Partial Shade (Prefers Morning Sun in Warm Climates)

Soil: Rich, Moist to Wet, Well-Drained Soil

Water Needs: Moderate to High; Prefers Consistently Moist Soil

Bloom Season: Mid to Late Summer

Fertilizer: Light Feeding in Spring; Avoid Excessive Fertility

Features: Brilliant Scarlet-Red Flower Spikes, Strong Pollinator Appeal, Native Perennial

Uses: Perennial Borders, Rain Gardens, Pollinator Gardens, Moist Garden Areas

Patent: ❌ Not Patented

Propagation: Division or Seed

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

More About Lobelia ‘Cardinal Flower’

Cardinal Flower is a striking native perennial known for its vivid scarlet red flower spikes that rise well above the foliage in mid to late Summer. The intense red blooms create a dramatic vertical accent in the garden and are almost impossible to miss when they come into flower. Each spike is lined with tubular blooms that seem to glow against the green foliage, creating one of the most vibrant displays you will see in a perennial border. It is one of those plants that instantly draws the eye, especially when planted in groups where the color can really stand out.

Unlike other Lobelias many gardeners are familiar with in containers, Cardinal Flower establishes itself as a long lived perennial presence in the landscape. Over time it slowly increases in size, forming a sturdy clump that returns reliably each year when planted in the right conditions. The foliage itself forms a tidy base that supports the tall flowering stems, giving the plant a balanced structure that works beautifully in naturalistic plantings. When planted thoughtfully, Cardinal Flower becomes a reliable late season focal point in the garden.

Why We Like It (Our Trials)

In our trials here in the Upstate, Cardinal Flower has proven to be extremely dependable when planted in moist garden settings. Once it settles in, it returns each year with strong growth and consistent bloom, gradually forming a more impressive clump with each passing season. We have found that the key to success is simply giving it enough moisture and avoiding extremely dry planting locations. When planted in the right spot, it requires very little intervention from the gardener. 

The plant naturally grows upright without staking and holds its structure well through the bloom cycle. I particularly like the way it adds height and vertical structure to perennial beds without feeling bulky or overwhelming nearby plants. What really sets Cardinal Flower apart, though, is its pollinator value. Few perennials attract hummingbirds as consistently as this one. Every Summer when it begins blooming, hummingbirds seem to find it almost immediately, darting from flower to flower throughout the day.

Cardinal Flower vs. Other Lobelia Varieties

Cardinal Flower is a true perennial Lobelia grown for height, structure, and long-term landscape impact rather than seasonal container use. Unlike compact annual lobelias such as Hot® Purple, Cardinal Flower forms upright clumps that can reach 2 to 4 feet tall and produces dramatic scarlet flower spikes later in the growing season. While Hot® Purple is valued for early color and fine texture in spring containers, Cardinal Flower is planted as a permanent feature in perennial borders and moist garden areas.

When compared to more controlled annual selections like Magadi™ Compact Blue Bay and the Techno® White, Cardinal Flower again fills a very different role. Magadi and Techno varieties are bred for uniformity, tidy form, and heavy early flowering in containers and baskets, whereas Cardinal Flower prioritizes vertical presence and pollinator value. It is not suited for pots or edging, but instead thrives in consistently moist soil where it can return year after year.