Thinking About Landscape Design in Light of a Changing Climate
Featuring Allison Terry, Terry Design
We explore best practices and new techniques and materials, and think about optimal landscape decisions for long periods of drought followed by heavy periods of rain and high winds. Alison Terry of TerryDesign provides us with the following list to consider when designing our outdoor spaces.
- Select plants that work with our climate: Native Southern California plants and those from Mediterranean regions, or those adapted to our typically hot dry summers and mild wet winters. You may also consider selecting plants that are adapted to higher heat and lower moisture than we currently experience in our zone.
- Create carbon sequestration in your garden. More carbon is sequestered in our planet’s soil than in our plants and atmosphere combined. The companion principle to this is the no-till garden, where the soil food web is notdisrupted by tilling. Soil is living and mulch not only retains moisture and inhibits weeds, but it is food for the living organisms in the soil.
- Train your gardener to: Use an electric blower, blow at an angle to retain mulch, and let leaf litter decompose under trees and shrubs to become food for the plants.
- Use only organic fertilizers. Synthetic fertilizers slow down humus formation and carbon storage in the soil.
- Take the long view in your plantings—let go of the “instant landscape” concept. Plant at appropriate distances to allow for future growth. This will minimize the amount of green waste your garden generates and as a result require less gas-powered trimming.
- Grade your property for maximum rainfall infiltration into the groundwater within your property instead of piping it directly into the city stormwater system. The layers of your garden soil act as a filter for pollutants before the water reaches the aquifer. Create dry stream beds, bioswales, infiltration pits, rain gardens, etc. Plant deep rooted plants on hillsides to retain soil and avoid erosion. Iceplant is shallow rooted and becomes top heavy when wet, contributing to erosion.
- Biodiversity is a critical issue and every little bit helps. Los Angeles is a biodiversity hotspot. The Los Angeles Bureau of Sanitation measured the Singapore Index on Cities’ Biodiversity as a first step to creating measures to help biodiversity. Ornamental plants do not support native insect and bird life. Native oak trees are the most important supporters of insect and bird life. Understanding how simple swaps in our plant palette can make a big difference on insect and bird survivability is a first step towards improving biodiversity and combatting climate change.
- Irrigation concepts: Deep watering provides deep root structures for trees and shrubs that enables them to survive drought better and withstand strong winds. Planting trees in or next to lawn areas encourages shallow rooting systems, making trees more susceptible to toppling over. Drip irrigation, if installed and maintained properly, is one key component to water conservation. I prefer Netafim drip for smaller planting areas around hardscape and MP Rotators for large planting areas and lawn. Use a smart controller that has a rain gauge.
- Lawn: In general, plant lawn only where needed for active recreation. There are many low green groundcovers that not only require less irrigation but negate the need for weekly mowing. Letting lawn grow a bit longer not only sequesters more carbon but encourages deeper rooting making it more drought tolerant. I use only warm season grasses like St Augustine or Bermuda, or a Southern California adapted grass like UC Verde for active recreation.
- Building materials: I prefer wood for decking over composites that contain petroleum and have a high embodied energy. I let wood weather to a natural gray vs continual staining, painting, or oiling. There are many technological advances being made in the wood industry to steer consumers away from tropical hardwoods. These woods use heat or bio liquids to replace water in wood, contributing to its stability and longevity, and making a soft wood such as pine or ash rate as hard as a tropical hardwood.
- Fire: Understand the concepts of defensible space around your house and how a fire moves through vegetation. Plants are fuel for fire and strive to create a 5’ wide hardscape or herbaceous path around your house for firefighters. In high fire danger areas, highly flammable plants, such as Hollywood Juniper, should not be planted within a 30’ perimeter of your house, and avoid creating ladders between shrubs and trees that can make a fire jump from the ground plane to the roof. Hire experienced and licensed arborists to prune and thin trees for fire safety and also for wind passage.
- Source locally: Many lower cost materials come at a huge cost to the environment in less developed countries. I look for materials made in the US and preferably within CA to lower the embodied energy costs.
- Solar power: Rolling blackouts may become a common occurrence each fire season. Solar panels and a backup generator allow you to maintain some independence from the grid.
- Solar water heating: Consider this for your pool if your roof space and configuration allow it. Note: your pool can also become a fire pond if necessary, using a gas-powered pump.
Note: many city codes now take into account many of these concepts, making them a requirement for new construction instead of a choice. Irrigation plans must meet the state water budget set out by MWELO. Low impact development plans (LID) ensure that there is a balance between roof and hardscape runoff and infiltration, or at least runoff is filtered before it reaches the city stormwater system if infiltration is not permitted on a site.
For more examples of Allison's work, please visit her website. All photos taken by Christian R. Terry.