Selecting plants for sustainable outdoor spaces

In celebration of World Landscape Architecture Month, April 2023

By Erik Jones

lanting design in Alaska can be a challenge given our northern climate and wide range of environments. Plant selection can make or break a planting design, so it is essential to consider several issues before putting anything in the ground. Luckily our state’s landscape architects can help make this task a little easier. Here are some of the things we think about when creating planting designs and selecting plants.

Depending on a project’s goals, understanding local land use or zoning code regulations may be important. Most backyard or residential projects will not require any code review. However, if your project is larger—for example creating a new development or improving a parking lot—you will likely need to explore the zoning code. In Anchorage this is Title 21 Chapter 7, Design and Development Standards.

Based on a parcel’s zoning and the adjacent property, you may need one of several landscape plantings along the perimeter of the lot. Code dictates minimum planting bed widths and the density and types of plants that meet the requirements. If you are lucky, the lot will already have a nice buffer of native vegetation that helps meet the code after an assessment. Jurisdictions outside of Anchorage have other requirements.

The next step in selecting plants is to determine the hardiness zone. Alaska is a vast state with diverse microclimates and ecosystems, which means that hardiness zones can vary significantly. The USDA Hardiness Zone Map is a useful tool that provides a range of lowest average annual winter temperatures for a given area. For example, most of Anchorage is within Zone 4b (-25° to -20°F). Once the zone is identified, you can choose plants rated to survive at those temperatures. Keep in mind that the higher the number of a hardiness zone, the greater selection of plant species to choose from. A lower zone number limits your plant choices.

There is a wealth of online information for researching plants. Not all sources are reliable, and often it can be difficult to find local recommendations. A great resource to start with for local plant selection is Landscape Plants for Alaska. The site lists trees, shrubs, and vines suitable to landscapes in Alaska. You can search by common or botanical name. It even simplifies the hardiness zones into regions of Alaska to make survivability in your area a little easier to understand.

Native plants are usually an excellent choice for a planting design because they are well-adapted to the local climate and require less maintenance. They have evolved to resist local pests and diseases, making them more resilient than non-native species. Using native plants also helps support the local ecosystem by providing food and habitat for local wildlife. Local nurseries are more likely to carry native plants, but they can be difficult to source in large quantities.

Another factor to consider is whether the plants you have chosen are invasive—or if in the future they could become invasive. Prunus padus, or Mayday tree, is one species that is no longer recommended for planting as it is highly invasive. And Alaska’s climate is warming, which means the hardiness zone of a specific location today may change in the not-too-distant future. On the flip side, a warming climate may open the door to more plant choices and allow a more varied landscape.

When selecting plants for landscaping in Alaska it is essential to consider their maintenance requirements. Some plants require regular pruning or pest control to thrive (think moose fencing), while others can be left to grow naturally. The establishment phase for plants is often the most critical. Plants need regular water and weeding before becoming more hands-off. Consider your level of commitment to maintaining a landscape design and choose plants that fit your situation.

To sum up, selecting plants for landscaping in Alaska requires careful consideration of several factors, including code regulations based on project size, hardiness zone, native status, invasiveness, and maintenance requirements. Taking the time to select the right plants is an important first step in creating a beautiful and suitable landscape design that thrives in Alaska’s unique environments. Our local landscape architects are an invaluable resource who will help you achieve these outcomes.