Interesting Facts About Wildflowers

Gayfeather can resprout after fire from underground corms.

Gayfeather can resprout after fire from underground corms.

Viewing fields, slopes, roadsides and meadows filled with colorful arrays of blooming wildflowers is one of the great gifts of life. While we appreciate the amazing beauty wildflowers give us, we seldom consider the marvelous mechanisms at work to repeat this show year after year. Annual wildflowers last for just a season and have to grow anew each year. Perennial wildflower plants last for several seasons, but need to produce enough new plants from seed to maintain the population. The endless variations are fascinating.

Pollination Mechanisms

To set seeds, flowers need to be pollinated. Many wildflowers have intricate structures to attract specific insects. The western prairie fringed orchid (Platanthera praeclara, U.S. Department of Agriculture hardiness zones 1 through 9) has night-fragrant white flowers equipped with a long spur containing nectar. Nocturnal hawkmoths with long tongues that exactly fit the spur size visit the flowers for nectar and transfer the pollen masses that get attached to their eyes. Southwestern pipevine (Aristolochia watsonii, USDA hardiness zones 6 through 10) has purplish-brown flowers with an opening that resembles a mouse's ear, and a musty smell. Small biting flies (ceratopogonids) crawl into the flower looking for a blood meal, get trapped in the flower overnight and exit covered with pollen.

Seed Dispersal

Seeds formed after pollination occurs must be carried from the mother plant to places they can germinate. Filaree (Erodium cicutarium, USDA hardiness zones 1 through 10) has twisted awns attached to the seed. Seeds explode away from the mother plant or attach to animal fur and socks to travel, then drill into soil when moisture expands and contracts the awn corkscrew. American Bittersweet (Celastrus scandens, USDA hardiness zones 3 through 8) has seeds covered with a red-orange structure called an aril. The aril provides tasty food for birds and small mammals. The animal digests the aril and eliminates the clean, ready-to-sprout seed in its feces.

Seed Dormancy

In desert areas, winter rainfall is erratic from year to year. Wildflower seeds have varying amounts of chemicals that inhibit germination in their seed coats. For a given species, some seeds germinate with just half an inch of rainfall. Others won't sprout until additional rain, perhaps in different years, has washed over the seed. Some seeds remain viable in the soil for decades before conditions are just right and they can grow. This is built-in insurance against all the seeds sprouting at once in unfavorable conditions and not reproducing. A California annual wildflower, whispering bells (Emmenanthe penduliflora, USDA hardiness zones 4 through 10), is native to chaparral, a fire-controlled plant community. Seeds won't germinate unless exposed to fire and smoke.

Perennial Wildflowers

Perennial wildflowers native to Midwestern prairies survive the periodic burning prairies undergo. Gayfeather (Liatris speciosa, USDA hardiness zones 3 through 10) re-sprouts from an underground corm which lives for 11 to 17 years. Purple coneflower (Echinacea angustifolia, USDA hardiness zones 3 through 9) possesses tuberous roots that survive fires and re-sprout. Many perennials have leaf modifications that help them survive harsh conditions year to year. Bush monkeyflower (Mimulus aurantiacus, USDA hardiness zones 7 through 10) has sticky leaves that help reduce water loss and repel plant eaters. Leaves of desert marigold (Baileya multiradiata, USDA hardiness zones 7 through 11) are covered with white hairs to reflect sunlight and reduce water loss. Desert globe mallow (Sphaeralcea ambigua, USDA hardiness zones 7 through 10) possesses star-shaped hairs on leaf surfaces that can break loose and irritate skin and mucous membranes.

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