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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Hummingbirds can't resist the brilliant crimson cardinal flower. © Donna Krischan

August 2004

Red in the yellow month

Cardinal flowers flag down hummers in the heat of summer.

Anita Carpenter

Nectar stored deep inside the brilliant crimson cardinal flower tempts hummingbirds and insects.

© Donna Krischan

August is the yellow month. Meadows are full of flowering goldenrod. Yellow armies of insects are on the move as soldier beetles climb those goldenrod and ambush bugs hide in the blossoms. Lemony yellow sulphur butterflies congregate at moist areas to sip minerals before flitting about to find a mate. Yellow goldfinches, the last birds to nest, are still intent on parenting responsibilities.

Grasses too are turning yellow as their yearly cycle completes. Crops are starting to take on the yellowish hues of maturity. The first yellow leaves on poplars and willow trees signal autumn's approach.

August also brings purples and reds, but I must seek out these bursts of color. New England asters with purple rays and yellow centers compete for attention in the fields. Blue-purple bottle gentian snuggle among the taller plants in wet spots and prairies. Red is less common, but in damp meadows, wet open woods and along streambanks, the glorious red of the cardinal flower clamors for our attention.

Cardinal flower prepares all year for its moment in the August sun. The perennial plant overwinters as a small cluster of rosette leaves growing near the ground. In late spring, a single flower stalk grows from the rosette eventually reaching three to four feet high. The deep red flowers begin to open in July and reach their peak in August. The stalk continues to grow, producing more flowers along its length.

Each delicate cardinal flower (Lobelia cardinalis) is a tube that points upward. The end of the tube settles into five petal-like divisions – two point up and three point down. The "petals" seem to offer a stable platform for insects to alight and walk into the flower, but they can't reach the reproductive structures located near the base that's full of nectar.

This flower is tailor-made for pollination by hummingbirds and day-flying moths. Each flower matures with a male stage, when light yellow pollen rests on the tip of the tube, and a female stage, when a y-shaped stigma projects beyond the tube tip. When a hummingbird hovers and drinks from the nectar-containing tube, the bird touches the pollen with its forehead, then transfers it to the sticky stigma of other flowers as it feeds, fertilizing the flowers.

As they mature, pollinated flowers form dry capsules. When it's time to release seeds, the capsules split open. Two compartments each contain hundreds of minute orange-brown seeds. Those seeds may fall on fertile ground and germinate or drift on water to colonize a new area on some distant shore.

Inspecting cardinal flower is worth a few moments of your time, though you may get wet feet taking a closer look. If we could only hover like the hummer for a bird's-eye view we could enjoy the dense cluster of nectar-laden, cardinal red flowers in the hot, yellow month of August.

Anita Carpenter puts up with wet feet treading the fields and streamsides in all seasons.