Dayton Innovation Legacy is made possible in part by the Ohio Humanities Council, a State affiliate of the National Endowment for the Humanities.

Copyright © Engineers Club of Dayton Foundation. All rights reserved. Contact Us. Web design by MartelArt.


Club Site | Club Blog

  “Where Professionals Connect”

Home Innovators Valley of the Giants Engineers Club Story Inventive Ohio Ropewalk Contact
YouTube Videos.
Buy the Book.

The Siebenthaler Family—Cultivating Success Across Six Generations

Beautifying Dayton since 1870, the Siebenthalers continue to succeed by adapting to a changing market, by innovative tree patents, and by involvement in their industry and community groups like MetroParks and the Beaver Creek Wetlands Association. Bob Siebenthaler is a member of the Engineers Club of Dayton.

“Man probably isn’t  going to be the last critter on this earth.”

 —Bob Siebenthaler



Cultivating Success Across Six Generations
By Mark Martel

Companies have life spans, just as do people or plants. Today, only half of small businesses survive for at least four years. By year forty, let alone by year 140, only a tiny few remain in operation. The Siebenthaler Company is one of the rarities. Begun around 1870 it is now one of the nation’s oldest plant nurseries, in its sixth generation of family ownership in Dayton, Ohio.

Siebenthaler family members continually adapted their business as customers shifted from farmers to homeowners to larger organizations. While growing the horticulture business, they also found time to contribute their unique skills to community groups like MetroParks, and to make major gifts to conservation groups like the Beaver Creek Wetlands. What are the secrets to such continued vigor? Let’s begin with the family tree.

In 1831, the Swiss-German Siebenthaler family set out for America and settled in Cincinnati. A cholera epidemic drove them to nearby St. Peter, Indiana by 1834. There in a tiny house heated by cattle living on the floor below, son George learned to raise hops for brewers, though he had never been a farmer. George and brother Phillip often walked the 40 miles back to Cincinnati, earning the considerable sum of five dollars to play fiddle and clarinet (about $120 in today’s dollars).

In 1867 George moved to Dayton near today’s Siebenthaler Avenue and Catalpa Drive. There he built a farm, from which son John founded a nursery business in 1870 (1872 according to some records), selling fruit trees, berry plants, and grape vines at a local market at first.

The Dayton farm grew from eight to eighty acres, as the nursery began to cultivate roses and enter the landscaping arena. The city grew like Topsy alongside, from 30,000 souls in 1870 to 60,000 in 1890, doubling again by 1910 and yet again by midcentury.

By 1920 the newly incorporated Siebenthaler Company’s fruit tree sales had been largely replaced by ornamental shrubs and trees that were produced and shipped to all parts of the country. 140 acres were bought south of town in what would become the city of Moraine. At least four of John’s children brought different talents to operations as the third generation of Siebenthalers. Son Clarence grew the landscaping service, son John D. developed new plants and son Wilber ran operations with sister Mary Siebenthaler Wilson.  The world began to take notice.

A 1929 Dayton newspaper wrote: “There is no need for any person to visit the Washington Botanical Gardens, for right here in Dayton, at the Siebenthaler Nursery, the study of indigenous ornamental shrubbery is complete.” ‘

The company was able to prosper during the Depression. John D. developed over 30 varieties or oriental poppies which proved popular, as well as lilacs and shade trees. The landscaping division also grew, over time beautifying major Dayton locations such as NCR, the Dayton Art Institute, Dayton Public Library and major residences like those of Orville Wright and inventor Charles Kettering.

As the family and business grew, both branched out to additional properties in Moraine and Beavercreek. The growth would sow the seeds of later conflict as more descendants tried to share the business.

John’s nephew Robert, or Bob as he likes to be called, recalls that “As a young person I had an opportunity to meet Orville Wright. As a matter of fact, one day my father Clarence dropped me off at his office for, oh, an hour. And he enthralled me with all the little toys he liked to make.” Bob met other prominent Dayton innovators like Colonel Deeds and Charles Kettering as well. Orville and Wilbur Wright’s sister Katharine was in the Siebenthaler wedding.

The famous Californian Luther Burbank, responsible for 800 plant varieties, had helped inspire the Plant Patent Act of 1930. The act offered a plant’s “inventor” exclusive rights to their work for 20 years—at least theoretically; plants were easy to copy. The developer of the first tree patented in 1935, the Hass Avocado, lost heavily. “Growers would buy one tree…then re-graft their whole grove with the bud wood from that one tree.” Siebenthaler’s sought ways to profitably succeed in this new field.

Clarence and son Bob spotted some distinctive Honey Locust trees while driving up to Bob’s college. One lacked the usual thick masses of thorns along the trunk. It proved seedless, but the nursery figured out how to propagate genetically identical trees through budding.

The Siebenthaler Comapny applied in 1947 for its first patent for the “Moraine” Honey Locust. They received the low patent number 836, and claim it as the first shade tree ever patented. The locust was a great success—the small leaves and lack of seed pods minimized raking in fall, and being seedless meant more sales, which eventually peaked at 75,000. The tree was described as a radical innovation and a replacement for the American elm, which was dying off from Dutch elm disease. Today mature Moraine Locusts line many major streets in Dayton and surrounding communities. The royalties helped support Bob’s college tuition.

Bob went off to study Landscape Architecture at Michigan State through the Horticulture Department. He quickly met a girl named Joan he would later marry.  But while Bob was still a freshman his father Clarence died.

The college swelled from 8,000 to 45,000 students by his graduation, as WWII ended and vets enrolled on the G.I. bill. Soon those vets would be buying houses and planting yards.

But before Bob put down his own roots he served in the Korean War. There he ran a motorized heavy mortar outfit as company commander to over 300 men. Bob quickly gained experience the hard way in management and logistics.

After, he joined the family business in Dayton, which he had assumed would be run by his uncles. Instead, the company’s branching ownership was pruned back, and Bob ended up in charge.

Running a family business long-term can be like developing a new plant variety. Later generations must retains the original’s unique traits, yet vary enough to stay robust in a continually changing environment.

Bob jokes he kept the business alive past the typical third generation slump. He took the company into retailing, increased the landscaping business and continued his father’s work developing new trees before getting into community service and philanthropy.

Three later tree patents were granted in John D. Siebenthaler’s name: the Moraine Ash tree in 1958, Moraine Sweet Gum in 1980 and Wright Brothers Sugar Maple in 1981. One maple stands behind the Wright Cycle Company building in West Dayton. The original tree was spotted in a woodlot along Springboro Pike south of Dayton, sporting exceptional fall coloring and shape. A large example of the maple was donated to Carillon Park for the Dayton bicentennial, and had to be flown in by helicopter.

Go to Page 2>>

Resources and Links


Siebenthaler Family Record - 1831-1741 by Ira Alfred Siebenthaler (PDF)


Siebenthaler Family Archives at Wright State Universtity Library Special Collections and Archives


Siebenthaler Company History


The Siebenthaler Company


Five Rivers Metroparks History


Beaver Creek Wetlands Association


Robert K. Siebenthaler Legion of Honor Award


Robert K. Siebenthaler Dayton Daily News


US Plant Patent Act of 1930


Wikipedia entry on “Cultivar”


Hass Avocado History - First tree  patent ever issued


Siebenthaler Secrets to Longevity and Innovation

John D. Siebenthaler Tree Patents:


Moraine Locust (PDF) 1947


Moraine Ash (PDF) 1958


Wright Brothers Sugar Maple (PDF) 1978


Sweet Gum (PDF) 1978


Noting that Dayton is a “City of Innovators”, Bob Siebenthaler met Orville Wright, Charles Kettering, and Edward Deeds. Siebenthaler concludes that innovation is thriving today in the Dayton region.

Video courtesy of

View Slideshow>>

One of four trees patented by Siebenthalers, this Wright Brothers Maple was planted in 1992 next to the restored Wright Cycle Co. in West Dayton to honor Professor Rich Johnson. Photo by Mark Martel.  

>>View Slideshow