Mr. Horowitz excelled at creative marketing efforts, whether starting one of Pittsburgh’s first monthly magazines, developing Carlton Advertising agency or helping build Plantscape into a $10 million business.

One of his best marketing efforts came on behalf of a local luggage maker whose product had to compete against well-known national brands such as Samsonite. Friends connected Mr. Horowitz with entertainer Steve Allen, formerly host of “The Tonight Show,” who agreed to endorse the local brand by having an attached luggage tag bear his photo. A few years later, Mr. Horowitz got comedian Bob Hope to do the same.

His agency’s clientele also included Gimbels, Thrift Drug Co., Duquesne Brewing and Jiffy Foods Corp.

Mr. Horowitz might have stayed in advertising his entire career, but he was lured away to Plantscape in 1978. The landscape company, which had been founded five years earlier by his wife, Carole, needed marketing to help it grow.

Together, the couple transformed the company into one of the country’s largest, expanding it to 100 employees and later including artificial plants and outdoor landscapes. He went on to serve as chairman of the interior division of the Associated Landscape Contractors of America and helped create the Plants for Clean Air Council, serving as its first chairman.