Meet Your Neighbors

Grooved Yellow Flax:
Thrill on a Hill

When grooved yellow flax (Linum sulcatum) makes its annual appearance this summer, it won’t be scattered along the highway or obvious to people strolling in the park. Rather, it will pop up on dry gravel hill prairies of sandy soil and limestone, where growing conditions are rough and only specialized plants can survive.

Standing as low as 6 inches and sometimes reaching 28, this summer annual has slender stems that give way to ascending branches. From late July to mid-September (peaking in mid-August), hikers can look for its small pale yellow flowers, about the size of a nickel, with five overlapping petals. Like most flax, a few flowers bloom each morning and the petals drop off by midday, often falling in the slightest breeze.

Though most flatlanders will laugh at anyone suggesting our region has alpine conditions, the species that do well on natural gravel hills have adapted to extremes similar to those of more mountainous settings. Found growing on the steepest slopes, and often in bare blown-out spots, grooved yellow flax shares characteristics with mountain plants.

“It’s pretty wiry and low growing,” says Tom Vanderpoel, a member of Citizens for Conservation, which is reintroducing it in a restoration project in Barrington, Illinois, at Flint Creek Savanna. “It’s their way of adapting to conditions of drought, sandy soil, and gravel. It hunkers down to get out of the wind on the hills, and it has a low profile to adapt to the lack of moisture and nutrients and the quick pace of drainage in gravelly areas.”

The species can be found in most states from the Great Plains to the Atlantic. Though neither endangered nor threatened in our region, it is still a rare treat to see one.

The plant’s scientific name comes from Linum, Latin for flax, and sulcatum, meaning furrowed, a reference to the grooves on the stem and branches. The word Linum is as versatile as the flax itself. It forms the root of a number of words including line (as in rope, chord or fishing line), lint, linoleum, lingerie and linnet, a songbird that feeds on flaxseed.

If grooved yellow flax ever went to a family reunion, it would likely be intimidated by its industrial European relatives. For thousands of years, other members of the flax family have provided civilization with a rugged fiber that has been used to make fishing lines and nets, linens, sail cloth, and lamp wicks. Linseed oil from its seeds has been used medicinally to fight everything from upset stomachs to coughs and burns.

As for grooved yellow flax, “It’s just a little plant that hangs out with limited competition,” says Vanderpoel. “But it fills a niche. In restoration, if it wasn’t there then some nasty weed would take advantage of the void.” Kay Havens of the Chicago Botanic Garden adds, “It’s not eaten by deer so it’s good to have in your garden.”

Hikers may see flax’s yellow bloom mixed with the purples and creams of other hardy hill ramblers such as purple prairie clover, round-headed bush clover, and prairie cinquefoil. And since the search for flax will probably land hikers on the top of one of our beautiful gravel hills, chances are they’ll also be treated to a prairie or savanna stretching out below in full bloom. In the words of one admirer, “If you’re seeing grooved yellow flax, you’re probably getting a great view of everything else, too.”

—Terry Stephan