A native Wisconsin wildflower, Cardinal Flower (Lobelia cardinalis) is known for its bright scarlet-red flowers that attract hummingbirds and butterflies. Flowers appear on tall spikes in late summer and add a splash of color to the perennial bed or naturalized area. Often a short-lived perennial, it can self-seed, which helps to sustain its presence in your landscape. Provide moist soil, rich in organic matter, to see this plant thrive.
Use Cardinal Flower in shade perennial beds, in the middle to back of mixed borders, and in naturalized woodland areas. This plant is suitable for rain gardens, wet meadows, and along streams or ponds.
Cardinal Flower is a magnet for attracting several desirable species to your yard, including ruby-throated hummingbirds and the black, spicebush, and pipevine swallowtail butterflies. Bumblebees use the flowers for nectar and small halictid (sweat) bees collect their pollen. Most mammals will avoid nibbling on this plant, as it contains unpleasant-tasting compounds, making it deer-resistant.
Site it in a moist area in part-shade. The plant can tolerate full sun but will require mulching and consistent moisture to ensure the roots stay cool. Amend soil with compost when planting and add organic mulch (shredded bark or leaves) periodically to increase organic material content in the soil.
Cardinal Flower is fairly low maintenance. Plants may be divided every 3-5 years, but often are short-lived. Cut back flower stalks in late fall if desired and watch for seedlings in spring if spreading is a concern.
Cardinal Flower has no major disease or insect issues. Slugs may periodically eat the leaves but prefer hostas and other plants over this one. Mammals, including deer and rabbits, will generally avoid eating it as well.
Cardinal Flower is a member of the Lobelia genus, and contains an alkaloid called lobeline, which discourages animals from feeding on it. Lobeline is toxic to humans, so be mindful when siting it around children and pets.
An often-cited drawback is that it’s a short-lived perennial, lasting only 2-3 years in a typical landscape. However, proper mulching and moisture can help prolong its lifespan, and the plant can self-seed if conditions are right.
Despite its name, Cardinal Flower does not attract cardinals. Rather, the name is derived from the dark scarlet bloom color that is reminiscent of the robes worn by Roman Catholic cardinals.
Pair it with other shade tolerant plants, including Hostas, Ferns, Astilbes, and Lungworts. Great Blue Lobelia or Blue Flag Iris also pair nicely with this plant, providing a nice color contrast with the bright red blooms.