The tree lawn, otherwise described as the parkway, planting strip, or even the hell strip, is the space between the curb and the sidewalk. Generally, landscape architects specify turfgrass for these hostile environments. I can’t think of a single circumstance where turfgrass should be located in these areas.
High water-use turf should only be installed where it can be utilized for recreational or passive activities, such picnicking or dog walking.
The tree lawn is not conducive for these activities due its to the proximity to traffic.
Turfgrass adjacent to the curb inevitably produces water run-off every time the irrigation runs. In Colorado, people generally irrigate high water-use turfgrass two to three days per week. That means that we are sending clean, treated water to storm sewer two to three times per week! Furthermore, many of the tree lawns installed are very narrow, four to six-feet wide is common. If lush turfgrass is still desired in the tree lawn, there is an alternative. A netafim irrigation system, a type of drip irrigation, provides water beneath the turfgrass directly to the roots. Netafim has an initially higher cost for installation, and can be difficult to maintain.
Our rivers are running dry, making this water waste unacceptable.
ALTERNATIVES TO HIGH-WATER USE TURFGRASS
Instead of using turfgrass, xeriscape principles should be applied. Low water-use plants irrigated directly at the base of the plant via a drip irrigation system is the most efficient alternative. The groundplane, beneath the plants, may include decorative rock, organic wood mulch, or 3/8” fine rock (breeze). Rock is available in a variety of colors, sizes, and textures, making it easy to complement the surrounding development.
The use of shrubs, perennials and ornamental grasses, when designed properly, is more aesthetically pleasing and certainly more responsible than turfgrass. Understandably, the upfront cost is higher utilizing plant material, however maintenance and water costs make up for this very quickly. Living in an arid desert, an argument can be made that xeriscaped tree lawns do a better job of fitting in contextually. If we weren’t so accustomed to seeing green grass everywhere, the turfgrass might otherwise appear out of place.
Before your mind takes you to removing all plant material in the tree lawn, please consider aesthetics. An artifical turf tree lawn or a rock-only tree lawn both require zero water, however are they attractive? We must consider the balance of aesthetics and conservation – a cardinal room of the triple bottom line. The aesthetic of artificial turf can be unsettling, especially in the middle of a Colorado winter. Similarly, a rock-only tree lawn requires a high amount of weed removal maintenance. The best alternative is to provide low-water use plant material, densely planted providing little room for weed growth.
Conventionally, we’ve seen turfgrass in tree lawns as the default. It’s safe to say that it’s time for a change. We hope that you will be a part of that necessary change and improve our built environment in the process.
If you would like to read more on this topic, see “Colorado River Crisis,” describing the state of our river system.