Medians that Work
Medians are almost irresistible canvases for landscape artists. Designers are asked to design a median that recreates the nostalgic, shady streets and boulevards their clients remember as children. For safety reasons, the same shade canopy coverage, where limbs hung over traffic lanes on small rural roads of the past, is no longer allowed. Setbacks must be maintained to provide a clear path for cars and trucks, without the danger of falling limbs or crossover crashes.
Medians are traffic separators first. They are not permanent features and often are moved or paved to accommodate traffic changes. Expect errant drivers to cross into medians, especially if drivers direct their attention to dramatic landscape enhancements within them. When they see something they like, drivers turn their steering wheels toward those features instinctively, and then, boom! Median plants will likely need to be replaced on a regular basis. Include this as part of your maintenance budget.
If you are designing a median landscape, provide enough turf buffer around any plantings to allow mowers to maneuver around the beds without the need to hop into and out of traffic. Keep shrubs planted at least three feet from the median curb to allow room for branches to grow without extending into the traffic lanes. Keep the design simple, so maintenance in these dangerous spots is quick and easy.
For long stretches of roads with lengthy, curving medians, keep open sight lines through the plant material. This way, drivers can anticipate traffic movement ahead and see cars that might cross at open access points. Keep shrubs below 30 inches and median trees limbed up to at least 7 feet to provide a clear window for safe travel.
Don’t feel obligated to plant the entire length of long medians. Visually, a median planted from tip to tip can get monotonous when the continuous line of traffic separation is long. Breaks in the shrubs provides vertical and textural contrast and excitement to your planting. Turf areas provide visual relief and establish a rhythm to repeated dashes of mulched beds. Filling in the entire distance of a median with high-maintenance shrubs and ground covers will stretch your landscape budget without providing any additional visual impact. Give medians a break—or two, or three! If you are working with several medians in succession, you are not obligated to plant every single one with vegetation. Break up the look with simple, grassed medians between intensely-planted ones.
You can find more information about trees in The Advanced Guide to Roadside Design: How to Create Successful Public Landscape Projects, part of The Advanced Guide series.
Don’t feel obligated to plant the entire width of a median from edge of curb to edge of curb. Eliminating turf grass does not create a low-maintenance landscape solution. Turf grass is the easiest ground surface landscape treatment in areas adjacent to heavy road traffic. It can be maintained with mowing machinery. It provides a buffer for traffic-generated wind and reflected pavement heat.
Shrub beds in medians must be hand-weeded. You cannot escape the need to hand-remove volunteer weed and tree seedlings. They are abundant in the roadside seed bank, even when heavy mulch and landscape fabric are used. Weeds are transported to medians by adjacent vehicles, because the road acts as a corridor for distribution of new weed seeds. There is no practical chemical control for roadside shrub beds, and landscape crews are very resistant to hand weeding. It is a labor-intensive task. Budget for this and be sure to include the responsibility in maintenance contract specifications.
Creating beautiful medians along a stretch of highway is like adding jewelry to the landscape. Carefully plan how to accessorize the design for the most impact, without overwhelming the visual traveling experience. Use the money you save on limited accessories to do a focused effort of building refined and well-maintained spans of landscape material in just the right segments of the road.