RURAL PARKERSBURG - Daylilies are like potato chips.

Betcha can't plant just one.

University of Northern Iowa art professor Phil Fass easily has more than a thousand named and unnamed daylily varieties planted cheek-to-jowl in large beds on his farm.

It's easy to get hooked, and as Fass points out, there's always room to squeeze in just one (two or three) more. Hybridizing is a serious hobby pursuit for Fass, and his daylily gardens are populated with many of his as-yet unnamed seedlings.

"Daylily forms are so beautiful. They're living artifacts … it's hard to explain the psychological and intellectual challenge or the emotional charge I get from daylilies, especially seeing one of my seedlings bloom," says Fass, a member of the central region of the American Hemerocallis Society.

They are the perfect perennial - adaptable, low-maintenance and with few pest or disease problems, growing into large clumps.

Hemerocallis is the scientific name for daylily, belonging to the family Hemerocallidaceae. In the past, daylilies were placed in the lily family (Lilaceae), probably because the flower forms are similar. But daylilies aren't grown from bulbs like lilies and each flower lasts just one day. The word "hemerocallis" comes from the Greek words meaning "beauty" and "day," but "daylily" is used as one word. Numerous buds on a single stalk keep daylilies in bloom for weeks.

In Fass' daylily garden, there's hardly a form or color combination that isn't worthy of exclamation - or a second, covetous glance.

Blooms in hues of yellow, orange and red glint in the late summer sunshine, creating fiery fields of gold. Lavender, pink, buff and greenish blossoms peek out here and there, providing a place for eyes to pause in the midst of so much visual stimulation. Names like "Women Seeking Men," "Black Passion," "Green Extreme," "Power Lipstick," "Fear Not" and "As The World Turns" add to the intrigue.

Fass began his daylily collection as a fan of older cultivars, such as the reds, lavender and purple tetraploid daylilies introduced by James E. Marsh. Prior to his death, Marsh made arrangements with Charles Klehm and Sons Nursery, well-known in daylily circles, to release daylilies he wouldn't be alive to register. He work resulted in the "Chicago" introductions, such "Chicago Apache," "Chicago Firecracker" and "Chicago Arnie's Choice," among many others.

"Tets" as tetraploids are called, contain double the number of chromosomes as "dips" or diploids, and are "meatier" - more substantial with thicker stems and petals, larger flowers and more intense colors.

Through Marshalltown hybridizer Don Lovell and others, Fass' collection has widened and deepened to include some of the finest daylilies available by the country's best-known hybridizers, including spiders and unusual-looking daylilies classified as (what else?) "unusual forms."

The "bagel" or rounded blossom predominants, Fass explains. "It's the most familiar form. Petals are broad and reflex or curve back, edges can be ruffled or picoteed. The symmetry is appealing and sumptuous." Contrasting "eyes" and throats add interest, and in some varieties, blooms glitter with iridescence known as "diamond dust."

Fass has particular affection for spider and other unusual forms (UFs), which he describes as "the Rodney Dangerfields of the daylily world." Spiders are striking and nearly odd, with narrow, long petals spreading out like a spider's legs. Spiders must have a petal length that is four times the petal's width, a ratio of 4.0:1, Fass explains. There are numerous other variations under the heading "UF," including "crispates" or petal segments that are pinched, quilled and twisted, not to mention petal forms called "cascades" for a waterfall look and "spatulates" that are wider at the end like spatulas.

His conversations are laced with lingo like "cross," "fertile" and "pollen parent," and he makes the hybridizing process looks simple. Making the crosses is easy - famous daylily hybridizer Elsie Spalding described it as putting "pretty on pretty" - but finding that one-in-a-thousand isn't so easy. Fass uses a specific process for making his selections.

"You have to be aware of what other hybridizers are growing and make your own creative choices. It can take some time to achieve a daylily that is worthy of registering. Sometimes the first flower looks great and the next is junk," Fass says. "If you find that special one, it takes time to create the root stock needed to bring a new variety into the market."