Landscape Architects -- Experts on More Than Just Lawns and Gardens

· Indigenous vegetation and wildlife habitats. Faced with vegetated or natural sites, even within cities, diligent landscape architects study and advocate use of native plant species; they also worry about animals that inhabit or depend on a site's natural features.

· Existing built context. Designers also must document and consider everything constructed -- roads, bridges, retaining walls, buildings, fences, overhead and underground utilities -- on, under or around a site; existing structures influence landscape composition, pedestrian and vehicular access, land uses and views.

· Existing regulatory context. Like other factors, ordinances and regulations governing land use, site development, construction and conservation must be carefully researched, not only because they limit or prescribe design choices, but also because they must be followed to get building permits.

By analyzing all these factors, capable designers gain profound understanding of the nature of land, discovering both opportunities and constraints. Then, understanding the project site and context, they can make creative, prudent decisions about land forms, about patterns of movement and place-making, about where to build or not to build.

Only with such understanding can they develop specific design strategies for planting trees, shrubs and ground covers; for configuring paving and retaining walls; for introducing water features; and for installing structures, artwork, outdoor furniture and exterior lighting.

Like architects and engineers, landscape architects are also concerned with issues of sustainability. They can specify recycled landscape construction materials, avoid disturbing sensitive natural areas, prevent erosion, make paved surfaces permeable, collect and use rainwater for irrigation, and deploy trees and shrubs to keep buildings cooler in summer and warmer in winter.

So if you hire a landscape architect to help you redo your scruffy yard, remember that, in the plan showing where to build the terrace and plant the Leland cypresses, the landscape architect has probably invested much more thought than the drawing may suggest.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.