At Penn, he studied with Ian McHarg, the Glasgow-born urban planner and ecologist, whose book Design with Nature revolutionized the way landscape architects can shape the land.
In the studio, they practiced his “layer cake” technique of overlapping transparent sheets of Mylar, each with a schematic of hydrology, soil, and areas of forest, marshland or fragile dunes.
There he worked on commissions such as the Westway Waterfront Park on Manhattan's West Side and a new ecologically based corporate headquarters for Merck Pharmaceuticals.
Hollander Design has offices in New York, Chicago and Sag Harbor, N.Y., and a staff of 25 environmental planners, landscape architects and horticulturists.
When designing a landscape, Hollander focuses on what plants and trees are appropriate for the land, favoring native species and those that will survive in the existing soils.
[14] Hollander, writes J. Michael Welton in Ocean Home magazine, "views his profession's commitment to every landscape as akin to the Hippocratic Oath: First, do no harm.
"[15] Hollander has taught at the City College of New York and in the Graduate School of Fine Arts at the University of Pennsylvania, where he serves on the Dean's Council and has frequently lectured.