Maryland temperatures are predicted to increase 5⁰ F to 11⁰ F by 2100. Higher temperatures will cause native plants to experience more heat-related stress, a situation that will be made worse by longer droughts. Warmer temperatures will cause earlier leaf out and bloom times, de-synchronizing relationships between plants and their pollinators. Invasive plants will become even more aggressive because higher atmospheric carbon dioxide (CO2) levels preferentially promote the growth of invasive plants.
Some species will adapt to the changing climate, allowing them to maintain or even expand their natural ranges. Native species that still thrive in your region, for example, have adapted to all the climate change that has occurred so far. City native plants have also adapted to all the warming associated with the urban heat island effect, and they have done so in just a few decades.
As the climate warms, the temperature conditions with which a species co-evolved will move north or to higher elevations. But plants can’t just get up and migrate the way some animals do. Plants migrate through seed dispersal. For northward migration to work there must be large, contiguous blocks of natural area. Species that are adapted to life on Maryland mountaintops are in peril because there are no higher elevations to migrate to.
Plants in tidal habitats must also cope with sea level rise. As of 2018, around the Chesapeake Bay, sea level is rising at a rate of ¾”to 1” every 5 years. Additionally, tidal environments are being pounded by more intense storms. Unfortunately, upslope migration is often blocked by hardened shorelines.
There are several things you can do to make your native garden plants more resilient to climate change. For example, don’t plant natives in conditions that are too sunny or too dry for them, and avoid species that are near the southern end of their natural range. Gardeners can also help protect wild native plants by helping to preserve natural area corridors that species need for migration. You can get more detail on these topics by visiting our Native Plants and Climate Change webpage.
By Sara Tangren, Ph. D., Sr. Agent Associate, Sustainable Horticulture and Native Plants, University of Maryland Extension, Home & Garden Information Center (HGIC)