In the example below, we removed an old patio and retaining wall and installed Unilock Roman Pisa retaining wall and Unilock Brussels Premier patio. A waterfall was installed in the wall and flowering plants and shrubs were installed to complement the wall and patio. Spahn-Manning Landscape Company Inc. was originated in 1977 by David Spahn, landscape architect from McKay Nurseries. Robb Manning worked with David Spahn from the beginning and then took over the business in 1993. In addition to handling business and sales aspects of the company, Robb is also hands on in all of the company's projects.