Lobelia Cardinalis

Cardinal Flower 

The last “Plant of the Month” for 2023. Since we really don’t have any native plants blooming at Christmas (other than, perhaps, Hamamelis virginiana – American Witch Hazel), I thought I’d do the next best thing and at least pick a plant that has “Christmas colour”. For that I chose the nice, cheery reds of Lobelia cardinalis, Cardinal Flower. 

This moisture loving, short lived perennial is a an essential rain garden or pond addition, and is sure to draw hummingbirds to your yard as it is one of their favourites (at least in my yard it is).  

As usual, the Plant Description and the In the Garden sections below are courtesy of Shaun Booth. 

Happy Native Plant Gardening! 

Common Name: Cardinal Flower 

Scientific Name: Lobelia cardinalis 

Family: Campanulaceae (Bellflower Family) 

Alternate Common Names: Indian Pink 

Plant Description: Cardinal Flower has an unbranched central stem that is light green and variably hairy. Leaves are attached to the stem in an alternate pattern and are up to 15 cm long and 4 cm wide but usually only get to half this size. The lower leaves have short stalks while the upper leaves are stalkless. Each leaf is coarsely toothed, sharply pointed, and usually hairless. Stems terminate with spike-like clusters of tubular, ascending red flowers, each measuring up to 4 cm long and 2.5 cm wide. The upper lip of each flower has two lobes that spread out sideways while the lower lip is divided into three lobes. A red style with a hooked tip rises above the upper lobes. Flowers turn into small capsules containing many tiny seeds. 

In the Garden: Cardinal Flower is nothing short of a showstopper! In midsummer it sends up magnificent spikes of scarlet red flowers that add a strong vertical presence to the landscape. Fortunately, herbivores tend to avoid this plant. 

Skill Level: Beginner to intermediate 

Lifespan: Short-lived perennial 

Exposure: Full sun to full shade (but does best in part shade) 

Soil Type: Clay to sandy, limestone-based soil and humus-rich soil 

Moisture: Moist to wet (needs constant moisture to thrive) 

Height: 30–120 cm 

Spread: 30–60 cm 

Bloom Period: Jul, Aug, Sep 

Colour: Red 

Fragrant (Y/N):

Showy Fruit (Y/N):

Cut Flower (Y/N):

Pests: No serious insect or disease problems, though snails and slugs may munch on the leaves 

Natural Habitat: Wet ditches and other low damp areas, seasonally inundated depressions in open woodlands, and along streambanks 

Wildlife Value: An important nectar source for hummingbirds and swallowtail butterflies (Papilionidae

A favourite of the ruby throated hummingbird.

Butterfly Larva Host Plant For: None 

Moth Larva Host Plant For: Pink-washed Looper Moth (Enigmogramma basigera

USDA Hardiness Zones: 3–9 

Propagation: Surface sow as the very tiny seeds need light to break dormancy. Seeds require 60 days of cold, moist stratification to germinate if starting indoors or spring sowing. Surface sow in the fall. Basal offsets may be separated to start new plants. Plants may also be started by taking stem cuttings (be sure to include one or two nodes), but to ensure the plants have developed a good basal rosette, the earlier these cuttings are taken in the season, the better. New plants may also be propagated by layering; in midsummer, carefully bend the plant over and pin it to the ground, lightly covering the plant with soil. New roots will grow along the stem and new shoots will emerge, which can be transplanted in the fall. 

The very fine, almost powder like, seeds of Lobelia cardinalis require light to germinate.

Additional Info: Though this short-lived perennial typically only lives for two to three years, it can carry on in your garden by dividing it or moving it every year or two. This plant is at its finest when growing with minimal competition in forested wetlands. Note that commercial garden centres often sell cultivars of this plant that may or may not be as valuable to wildlife as the true species. 

Native Range: 

Cardinal flower can be found throughout the southern Great Lakes region, wherever soils are moist enough.