Native Plants & Climate Change
Climate change is here right now, but oftentimes in the Northeast, that is not always obvious. The west coast has drought and forest fires, but rarely do extreme events such as hurricanes reach Maine. However, Maine’s average temperature has increased by 3 degrees, and average precipitation has increased by 10% largely in the form of winter and spring storms. This means that in the summer and fall, drought and fires will become more common, while flooding will increase in the winter and spring.
Along the coasts and Maine’s many watersheds, development such as filling in wetlands will cause a dramatic increase in flooding. Buffer zones have been replaced with landfills, levees, and dams.
A shift in temperature and seasonality has caused many plants to bloom earlier in the season, and helped the spread of damaging species such as the hemlock woolly adelgid and deer ticks. Many native and invasive species are changing their range, disrupting ecosystems and all manners of systems.
However, native plants can play an important role in mitigating climate change’s effects. Restoring wetlands and riparian buffer zones is an excellent way to lessen the effects of flooding. Root systems hold in the soil and absorb excess water, decreasing erosion that further exacerbates floods. Trees such as alders, dogwoods, willows, beech, and oak all grow in wet soils and are excellent trees to plant alongside rivers and streams. Smaller plants such as elderberries, striped maples, and a wide range of wildflowers also enjoy occasionally flooded soils. Riparian buffer restoration is often a project for town governments and the army corps of engineers, but homeowners can use the same principles on a smaller scale. Pay attention to where your yard floods and plant water loving species in that area. At Whaleback Nursery, we dig a system of canals that divert water to multiple micro-ponds where riparian plants are planted.
Ultimately, as climate change shifts growing zones northward, it will be imperative that we allow plants to adapt through assisted migration. This means moving plants who are at the end of their range into an area more suitable. Examples include the shagbark hickory and pawpaw trees. Shagbark Hickory thrives in zone 6 and only has small populations throughout Maine, likely from indigenous populations who planted and cultivated them for their nuts. As the climate warms, this will be an important tree to spread in what has historically been zone 5. Similarly, Pawpaws require warmer climates than Maine has to offer, however in sheltered microclimates, such as a south facing, wind-protected corner, Pawpaws may grow until the climate changes enough for them to thrive. For all plant introductions, great care must be taken so that another invasive species is not created, however humans will be needed if many plants are to adapt to a changing climate.
On a human level, decreasing crop yields will create shortages and rising prices, thereby making the need for homegrown perennial crops more important. A variety of smaller perennial and tree crops ensures that even if some plants die or don’t fruit due to environmental stress, there will be enough diversity so that some crops survive. Talk to your neighbors and form a community of growers, each specializing in the plants you enjoy and have the environment to grow.
