Climate Change and the Landscape Designer

As I searched for photos for this post, I was surprised by the number of plants that have been thriving through our seasons of extreme conditions. These are spring plants. Native grasses and perennials are most ornamental in the summer and fall.

Lilac hedge

Tree peony blossom

As a landscape designer, I take seriously the responsibility to provide my clients with the best information and direction. In all fields, knowledge evolves and recommendations and best practices are revised.

In the past, these changes for designers have been in the form of improved plant performance, varieties and maintenance and in a wider choice of paving and building materials. However, now with effects we see on our designed landscapes resulting from climate change, the challenge to adapt is greater.

Our prairie in early spring after a burn

Biokova geranium buds getting ready to bloom

Realizing I needed to learn more about climate change, I attended a talk by Scott Denning of Colorado State University sponsored by the University of Iowa’s Office of Sustainability and the Environment. Find more information at simpleserioussolvable.org and sustainability.iowa.edu. Another helpful link is exploratorium.edu.

Dr. Denning presents a “basic scientific story” about climate change in three parts: “How does it work, why is it bad and what are you going to do about it?” This was exactly what I needed. It added to my understanding of how our landscapes respond to climate changes. What can we do to slow these changes and how can we garden with changing climate?

Native ginger

So how does it work? It is all about heat in and heat out. The earth absorbs the sun’s heat and later emits excess heat into the atmosphere.

Due to the carbon dioxide (CO2) from emissions in the atmosphere, heat gets stuck and cannot radiate away from the earth’s surface. It is reabsorbed and re-emitted in all directions by greenhouse gases. Carbon dioxide warms the atmosphere.

Why is it bad? The weather becomes warmer. Some states like Iowa have greater heavy precipitation and then more evaporation and warming. The polar vortex this winter and flooding in the Midwest and elsewhere this spring are serious outcomes. Crop yields are reduced. Hotter and drier forested areas in the west are becoming more prone to fire, according to the Union of Concerned Scientists. “As the climate warms, moisture and precipitation levels are changing, with wet areas becoming wetter and dry areas becoming drier.” The potential is there for wildfires in the west to increase.

What are we going to do about it? According to Dr. Denning, “Stop setting things on fire!” Keep improving energy efficiencies, create an energy efficient economy and reduce population (we have in the United States). We can continue to develop energy efficient vehicles and architecture, and a non-fossil fuel burning economy. All this needs to be made cheaper for developing economies.

What have I observed in my and clients’ gardens? We have had long dry periods followed by heavy precipitation. Irrigation has become an option for lawns we had not considered in the past. Soaker hoses and emitter lines in beds and around trees and shrubs direct water only when and where it is needed. We plan for gardens that quickly cover and shade the ground to reduce water loss. We choose plants to absorb excess water after storms.

Pagoda dogwood (native tree)

Another approach related to water is planning for inundations by testing the ground for percolation rates, creating areas where water can collect before being absorbed, creating swales and directing water away from foundations and always trying to keep water on site. Runoff from properties carries polluted water into waterways and reduces groundwater stores. Water that percolates through the ground is cleaner than water that runs off hard surfaces and lawns.

Viburnum (native), variegated tulip, Virginia bluebells (native)

Shooting star in my prairie

The extremes of heat and cold weather and of large snow and rain events, stress plants greatly, particularly plants grown outside of their usual zones and nonnative plants. Plant choice has become even more difficult already with the growth of the deer population.

Creating resilient landscapes that can survive dramatic weather changes is necessary. Also, we need to create sustainable landscapes to provide habitat for the native animal and plant species that are still with us and that improve our gardens. Each front yard and back yard matters in the move toward moderating our climate extremes.

Snowdrift flowering crabapple

Clematis Henryi and allium

Royal purple smokebush (will dieback and need pruning), Siberian iris, columbine (native), yellow Baptisia (native cultivar), catmint

Redbud (native tree)