FIRST IMPRESSIONS: Lobelia cardinalis is a clump forming perennial wildflower with toothed lance shaped leaves. In late summer stems are topped by spiky racemes of vibrant scarlet florets. The blooms are irresistible to hummingbirds and butterflies. Plants prosper in filtered shade with moist soils or in wetter sunny sites.
HABITAT & HARDINESS: Lobelia cardinalis occurs in New Brunswick, Ontario and Quebec. The range extends through most of the United States.
Plants are indigenous to wet prairies, openings in bottomland forests, wet meadows, sandy or gravelly seeps, edges of ponds, creeks or ditches and borders of marshes, sloughs or swamps. This species can occur in sandy or non-sandy soils
Plants are hardy from USDA Zones 3-9.
PLANT DESCRIPTION: Lobelia cardinalis is a tap rooted clumping perennial that forms robust winter rosettes. In spring upright unbranched stems rise from a crown that occurs at ground level.
The stems are clothed in oblong to lance shaped toothed leaves. Blades are up to 6” long and about 1.5” wide. They are glabrous above and pubescent beneath.
In late summer foliage is topped by spires of firey red florets. The florets are tubular with a two lobed upper lip and a prominent three lobed lower lip.
The floral display lasts for 4-6 weeks ending in early autumn. Flowers are pollinated by ruby throated hummingbirds and are also visited by swallowtail and sulfur butterflies.
After flowering, small rounded capsules full of tiny seed form on the stalk.
Plants are 2-4’ tall with a 1-2’ spread.
CULTURAL & MAINTENANCE NEEDS: Lobelia cardinalis prospers in shaded to partly sunny exposures with moist humus rich soil. Plants tolerate sunny sites if sufficient moisture is present.
The species adapts to sandy loam and gravelly or clay soil but will not tolerate drought. In garden situations the soil should be amended with organic matter to retain moisture.
After seed are produced, the flowering stem and its roots die. New offsets soon form and generate their own roots. The small offsets are vulnerable in fall and winter and care should be taken not to bury them under thick mulch layers.
This species is considered to be a short lived perennial but in an appropriate setting it will self-sow and replenish the population.
Foliage is generally unpalatable to deer and other herbivores but is chewed by snails and slugs.
LANDSCAPE USES: This species is often used as an Accent, Grouping or Mass planting in for a Rain Garden, Wildlife Garden or Perennial Border. Lobelia cardinalis has Showy Blooms and is appropriate for Cottage Gardens, Low Maintenance Plantings, moist Meadows, margins of Water Gardens, and soggy Roadsides.
COMPANION & UNDERSTUDY PLANTS: Try pairing Lobelia cardinalis with Asclepias incarnata 'Ice Ballet', Anemone canadensis, Carex comosa, Chelone glabra, Eupatorium coelestinum or Osmunda cinnamomea.
Lobelia cardinalis ‘New Moon Maroon’ could be planted to add unique purplish foliage to the garden. Lobelia siphilitica could also be substituted due to comparable cultural needs and similar blue flowers.
TRIVIA: Lobelia cardinalis won the Royal Horticulture Society 1993 Award of Garden Merit.
Lobelia cardinalis was introduced to Europe in the early 1600’s. The common name “cardinal flower” was quickly adopted due to the similarity of the flower color and the garments of Roman Catholic Cardinals.
This species is a member of the Bellflower Family.
For more information on this plant, visit the USDA PLANTS Database: http://plants.usda.gov/java/profile?symbol=LOCA2