The fuel shortage that threatens to make travel across the U.S. heartland more difficult might also help make the trek more scenic and worthwhile.

The rising cost of cutting and tending roadside greenery is prompting Midwest highway officials to consider sowing native prairie species that demand little care.

Thus, the motorist of tomorrow driving from Toledo, Ohio, to Bassett, Neb., could witness what the early settlers saw -- rolling prairie grasses and prairie wildflowers, which botanists say would reestablish themselves in their old setting with full vigor if given the chance.

Instead of the trimmed right-of-way, until recently thought the desired standard, travelers would see a changing panorama of color, says Roger Landers, Iowa State University botanist.

"In June he might see the purple cornflower and the prairie clovers. In August the prairie sunflowers appear -- black-eyed susans, the yellow sunflowers, the ox-eye. The grasses start flowering in September and October -- the big blue-stem, little blue-stem, Indian grass, switch grass. These turn reddish after the frost -- other color of wine stains,' Willa Cather said."

Several factors have combined in recent years to encourage planting native species along highways. States began mowing less after the Organization of Petroleum Exporting Countries oil embargo of 1973-74, the first energy scare. State conservation and game agencies have sought to reduce roadside mowing and preserve more habitat for pheasants and other wildlife, which found less room for broods as farmers began "fenchpost-to fencepose" plowing and river bottoms were drained to boost farm output.

Native prairie grasses and wildflowers have several advantages over the introduced fescues and bluegrass or mowed species. The native species have to be cut only once every few years, to lessen the buildup of mulch. Originally, naturally caused prairie fires performed the mulch cleanup and reinvigorated prairie growth.

The native species, whose root systems dig eight or more feet down for moisture, resist the region's periodic droughts. Nebraska uses its prairie-planted roadsides as a "hay bank" to harvest for livestock when drought withers the cultivated alfalfa and other hay fields. And the native plants, which are perennials, rebuild topsoil and resist erosion.

The progress in planting native species along roadsides has been greater in the West than in the East.

Richard Madachy, Ohio Highway Department landscape architect, says his department is in the midst of preparing a proposal to include prairie species in a new maintenance program.

And Illinois, "the Prairie State," is pushing ahead on several roadside prairie plantings. On the Edens Expressway, a section of interstate 94 north of Chicago, a half-dozen acres will be planted to prairie flowers, not grasses, as the road is rebuilt over the next two years.

"There will be black-eyed susans, leadplant, sky blue and smooth aster, pale purple cornflowers," says Grant Castleton, landscape architect for the Illinois Department of Transportation. "The only problem is, it takes a couple of years to get them flowering. So you have to be patient. The first years they may look pretty bad. But in three or four years, they're beautiful. There will be a sequence of prairie flowers all summer long."

Iowa has been prairie planting along its 100,000 miles of roads since the 1950s. "In 1960 we started using native grasses in all rural seed mixtures," says Harold Dolling, landscape architect for Iowa's roadside development section.

In 1973, prairie advocates in Iowa estimated the state could use its 180,000 roadside acres to grow 440,000 tons of prairie hay, which is as good as cultivated hay for animal feed. A gradual replanting in Iowa, as 1 or 2 percent of the state's roads are rebuilt each year, might take a half-century, says Landers. But to speed up the process, chemical suppressants could be used to kill existing vegetation, and native seeds could be sown at a fraction of normal land-preparation costs.

Nebraska, farthest along with its prairie roadside, has reseeded three fourths of its 10,000 miles of state highway to native species. About 13 percent of its 93,000-mile county system has been seeded to natives.

"We've even put our Interstates up to (prairie) hay," says Richard Gray, agronomist for the Nebraska Road Department.

"Originally, Nebraska was one big sea of grass," Gray says. "Except for a few wild plums and burr oaks resistant to prairie fires, trees were restricted to the eastern one-eighth of the state.

"We are getting our (prairie) seeding done for $400 an acre-ground preparation, seed, mulch, labor. Seeding-introduced grasses would be almost as much. Seeds, at $40 to $55 an acre, are the smallest part of the cost."

Prairie seed prices are climbing, he observes, as demand has soared recently. Throughout the Midwest, state highway departments are meeting competition for seed from county conservation for seed from county conservation districts, mining companies that must restore land surfaces, farmers who want to idle land and even schools that want to establish prairie fields nearby.