Industry mourns the loss of John P. Denison

John P. Denison, founder and CEO of Denison Landscaping, one of the largest landscaping companies in the U.S., passed away peacefully in his sleep on May 25 at his home due to complications related to diabetes. He was 61 years old.

His company released the following statement:

It is with great sadness that we announce the peaceful passing of our founder, CEO, brother, father, friend, and boss, John P. Denison on May 25, 2017. John was a loving, caring, and passionate person whose singular goal in life was the happiness and success of his family and all of those around him. He will be missed but never forgotten.

The Denison Landscaping family will continue to honor John Denison’s memory by providing the highest quality service to our customers just as we have done for the past 44 years.

The following is an excerpt from his obituary:

John began cutting grass with one lawnmower out of the back of his car while attending the University of Maryland. After receiving a degree in Applied Horticulture, he started his landscaping business.

In 1975, John completed his first landscaping installation. By 1985, Denison was flourishing, growing from 3 employees to 60, and twenty years later, in 2000, numbered over 400 employees. Today, the company has over 700 employees and grows its own plant material on over 1,400 acres of land located in Prince George’s County.


Denison is a family operated business, and three of John’s children, Joshua, James and Katelyn, his brother, Duane and nieces and nephews work for the company. John is renowned for his relentless hard work and determination, compassion for those around him, and his devotion to family, friends and employees. These characteristics were the driving force behind John’s success in growing Denison from a single lawn mower to a multi-million-dollar company.

John never hesitated to ask others for help or make new friendships and business connections. He used his success at Denison to improve the lives of everyone around him.

After forty-four years in business, John continued to interact daily with employees from every division of the company, including new hires doing landscape installations. He could be found in the “yard” every morning from Monday to Saturday where the landscape crews loaded and prepared to leave for their job sites. He spent the rest of his day among the other Denison offices and tree farms. John’s office door was open to anyone. He cared deeply for his employees and made sure they knew how much they were appreciated.

The family requests memorial contributions be made to Christmas in April-Prince George’s County, 7915 Malcolm Rd., Clinton, MD 20735 or the Prince George’s County Police Foundation, Inc.- K-9 Unit Account, c/o Prince George’s County Police Headquarters, Office of the Chief, 7600 Barlowe Rd., Landover, MD 20785, ATTN: Prince George’s County Police Foundation, Inc. or the Accokeek Volunteer Fire Department, P.O Box 226, Accokeek, MD 20607 or the Religious Sisters of Mercy, 6100 Wolverton Lane, Clinton, MD 20735.


Denison Landscaping & Nursery Inc. is a family owned and operated full service Landscape contractor in the Washington, DC./Baltimore Mid-Atlantic Region since 1973. Currently, Denison Landscaping & Nursery, Inc. services the Mid-Atlantic region, which includes the Eastern Shore and Pittsburgh, providing a full range of landscaping services from commercial and residential design build to irrigation, maintenance and enhancements and wholesale division while operating over 750 acres of nursery production.


Upon learning of Denison’s passing, the National Hispanic Landscape Alliance (NHLA), issued the following statement:

The National Hispanic Landscape Alliance, (NHLA) is especially grateful for the support Denison offered to the vision and initiatives of the organization that benefits Hispanics in the industry. He was supportive of the organization from the beginning and was a great advocate for the Hispanic workforce.