Sustainable Landscape Design

Sustainable Landscape Design

What is a Sustainable Landscape

When our clients ask to create a sustainable landscape design for their project, or they tell us that they want Xeriscape Landscaping, the majority of the time what they are asking is for us to specify low maintenance, drought-tolerant plant materials.  While selecting the right plant materials for a sustainable landscape design is critical, there are additional sustainable landscape design principles involved with creating sustainable landscapes.

Benefits of Designing Sustainable Landscapes

While there are many benefits of designing sustainable landscapes, the following are, in my opinion, the top five:

    1. Lower maintenance (hence, lower maintenance costs);
    2. Lower water usage (hence, lower water costs);
    3. Reducing waste;
    4. Decreasing runoff; and
    5. Sustainable landscape solutions are better for the environment.

Sustainable Landscaping Principles

While there are many sustainable landscaping principles, the following are those that I believe deserve the greatest amount of attention:

1. Sustainable Landscape Design:

Creating a sustainable landscape always begins with a sustainable landscape design. Sustainable landscape designers need to ensure that they create a balanced relationship between the natural and manmade environment.  Having a plan in place BEFORE beginning the landscape installation is critical.

2. Improving the Existing Soil:

In most parts of the country, the existing soils we are given are not naturally the best when it comes to growing sustainable plants.  These existing soils need to be evaluated, and potentially modified, to get them into a condition where the plants will not only survive – but thrive.

      1. The Importance of Soil:
        1.  Holds water;
        2.  Provides nutrients to the plants; and
        3.  Allows water to reach the plant roots.
      2. How to Improve Your Soil
        1. Perform a soil test: You will want to conduct a soil test.  Take a sample both from an area that will be future turfgrass, and an area that will be a future planting area.  Both turfgrasses and plants have their own soil requirements, which is why they need to be tested separately.  If you want to nail it down even further, different plant materials have differing soil requirements as well.  Some like acidic soils, some like alkaline soils, some like high organic soils, some aren’t too picky…well, you get the idea.  Therefore, you may desire to conduct additional soil tests based upon the planting types in the different areas.
        2. Modify the existing soil: When you send the soil samples to a lab, ensure that you select a lab that also offers recommendations for modifying the soils based upon the plant type (or turfgrass) that you plan on installing there.  This may involve fertilizer, organic amendment, soil gypsum, lime, etc…  You will want to till these amendments in with the existing soil to create a homogenous mixture.

3. Limit Turf Areas

    1. The problem with turfgrasses is that they require a lot of fertilizers, herbicides, fungicides, and water.
    2. Limit the quantities of turf areas in your sustainable landscape design (substitute with groundcovers, low growing shrubs, or gravel…or any combination of the three).
    3. Also, select a species of turfgrass that is hardy to your area and does not require a lot of water or frequent mowing.

4. Efficient Use of Landscape Irrigation

    1. Use the right components in the right areas (drip for beds as opposed to spray heads, rotors for large turf areas, adjustable nozzles for spray heads, etc…)
    2. Implement water-saving landscape irrigation components
      1.  Install an Evapo-Transpiration (ET) controller to reduce over watering. ET controllers use weather data to calculate ET (ET = evapotranspiration; or, the evaporation of water from the soil and the plants themselves)
      2.  Drip irrigation places water directly at the rootball – eliminates water waste by applying water where needed and avoiding watering open areas that don’t need the water.
      3.  Pressure-regulating heads regulate the pressure coming out of the nozzle which can save water from misting (and being wasted) in high pressure systems. Utilizing these heads has (or will soon) become mandated in VT, CA, CO, HI, ME, and WA.  Rumor has it that MA and RI may be next.
      4.  Rain/Freeze Sensor: A rain and freeze sensor prevent the landscape irrigation system from turning on either after a substantial rainfall (rain sensor) or during a freeze (freeze sensor).
      5.  Flow Sensor: A flow sensor should be a standard on all irrigation designs.  Let’s say you have a broken sprinkler head or a broken pipe, you are going to waste a lot of water.  Since most irrigation systems operate in the early morning, you are not going to know that you have a break until your water bill arrives in the mail. With a flow sensor, that zone will be turned off by the irrigation controller when it detects the additional flow.  It will also provide a message to you on the display of the controller.
    3. Landscape Irrigation Design is Important for a Sustainable Landscape
      1.  Having an irrigation design will help ensure that you will have a water-conserving system installed.
      2.  Some General Contractors prefer to have landscape irrigation contractors submit a lump sum bid with the irrigation contractor doing their own design (the design is not submitted with their bid). With this, you don’t know what you are going to get with their design.  Most likely, they are planning to install a system that is cost-efficient, helping ensure they are awarded the job.  Plus, you won’t be able to competently compare their bids “apples-to-apples” as you could if you had a prepared design for them to bid from.
    4. Water early in the morning to avoid evaporation rate and to prevent the burning of the plant leaves by the reflection of the sun.
    5. Watering sustainable plants is still required…especially during the time period the plant is getting established. Also, it is a good backup measure during times of droughts.

5. Mulch

Mulch is one of the sustainable landscape products available.  A few of the benefits of mulching include:

a) Retains soil moisture,
b) Slows evaporation,
c) Protects roots from overheating, and
d) Helps suppress weed growth.

Depth: Maintain a 2 to 4” depth.  Recommend mulching twice per year at 1 ½” to 2” per application.  Keep mulch about 2” away from tree trunks and plant stems (avoids rot and insect infestation).

Types:  There are MANY types, sizes, and colors of mulch materials.

a) Shredded hardwood
b) Native
c) Pine Bark
d) Various Types of Gravel
e) And many more…

6. Specify Sustainable Plants

    1. Use hardy, proven, sustainable plants. Ensure these plants work well within your area.  This includes those plant materials that are drought-tolerant, require limited pruning, are not susceptible to insects or diseases, etc…
    2. Place the plants in locations where they thrive the best (full sun, shade, semi-shade, large open areas, small contained areas, etc…)

7. Appropriate Maintenance

    1. Mowing: Don’t scalp your lawn.  Scalping can cause burning of the turf’s roots and puts stress on the turfgrass which can make is susceptible to insects and diseases.
    2. Herbicides, Fungicides, and Insecticides: Here you have the option of going fully organic, fully synthetic, or somewhere in the middle.  Ensure you apply them only as needed, and per the manufacturer’s directions.

Additional Resources:  To learn even more about sustainable horticulture and landscaping or just to pick up some additional sustainable landscaping ideas, you may want to check out the Phipps Center for Sustainable Landscapes.

Evergreen Design Group is one of the top sustainable landscape architecture firms in the U.S.  Practicing sustainable landscape architecture is always a top priority – whether the projects we are designing are in California, Texas, Florida, or even Alaska…our sustainable landscape designers stay abreast of the latest happenings in the realm of sustainable landscape design.

Contact Us to learn more about how we can be an integral part of your design team.