This popular late-summer perennial blooms profusely from late summer to fall with brilliant red flower spikes that bloom from the bottom up, rising from rosettes of glossy, lance-shaped leaves. Erect stems with densely packed blossoms and slightly bronzed or purple-tinged green leaves grow 3-6 feet tall in full or part sun. Red lobelia appreciates full sun in colder climates, but in hotter areas it does well with some afternoon shade. The plant will be larger and showier and will produce abundant nectar in full sun. Because it’s found in moist areas in the wild, it should be sited in moist conditions, such as low or poorly drained spots. In drier conditions, add a layer of mulch around the plants and amend the soil with compost to retain moisture and promote healthy growth. Red lobelia is unusually resistant to diseases and pests, and is highly attractive to pollinators. It’s one of the best native plants for attracting hummingbirds.
Red lobelia’s beautiful, deep red color is reminiscent of the vestments worn by Roman Catholic cardinals (another common name is cardinal flower). This particular red is stunning in combination with other late-blooming blues and purples, such as great blue lobelia, purple coneflower, irises, ironweed, and penstemon.
Red lobelia plants are short-lived, usually dying after 2-3 blooms; however, offshoots and self-seeding will eventually colonize an area. The young offshoots can be removed and transplanted as needed. When older clumps begin to spread out sparsely, dig up the plants and divide the crowns for replanting. The basal rosette of leaves remains all winter, so don’t smother it. Flower stalks may need to be staked if exposed to strong winds or planted in shady areas. They can be trimmed back if they look leggy and untidy. Deadheading is not recommended as it will significantly reduce the amount of reseeding.
Native habitats include wooded swamps, marshes, along banks of ponds and streams, and moist woods. Use in borders, rain gardens, butterfly and hummingbird gardens, moist meadows, native gardens, edges of ponds or streams, shallow water gardens, or containers (they will need frequent watering). This plant is useful for stabilizing slopes with water runoff. It makes a nice cut flower although the stems leak milky sap.
Plant Characteristics:
Grows 2-4’ tall and 1-2’ wide.
Grows in full or part sun.
Requires moist soils and tolerates seasonal flooding. Adapts to clay soil.
Flowers are 1-2” long with 3 spreading lower petals and 2 upper petals that are all fused into a tube at the base. 5 stamens are fused into a tube around a 2-lobed stigma. Blooms appear on alternate sides along unbranched stalks from July to September. Color is red and occasionally white or pink. Fruit capsules contain numerous small seeds.
Alternate, lance-shaped leaves are sharply pointed, finely serrated, and up to 6” long. Erect stalks are light green, round, and hairy.
Wildlife Value:
Host plant to 5 species of Lepidoptera larvae, including specialist pink-washed looper (pictured here), greater black-letter dart, dark-spotted palthis, and red-banded leafroller moth. Large swallowtail butterflies and bees consume the nectar and pollen. Hummingbirds favor and frequently visit the flowers. Deer and rabbits tend to leave the plant alone.
Medicinal, Edible, and Other Uses:
Lobelias are somewhat toxic to humans and pets. They contain several toxic alkaloid compounds that can cause serious symptoms or even death if enough is ingested. Maybe fortunately, it has a strong emetic effect.
The Iroquois boiled the roots with chicory root and used the liquid to treat fevers. They also mixed the roots, stems, leaves, and flowers to treat cramps. The Pawnee used the roots and flowers as a love charm. Cherokee Indians used the plant to treat headaches. Currently, lobelia is sometimes used as an expectorant and for asthma. The addition of peppermint essential oil can help dampen the emetic effect and help open up the lung.
The alkaloid lobeline has been widely studied for its use for nicotine and amphetamine addiction.