Planting for a Changing Climate
This past week much of Long Island experienced its first heat wave of 2021, with temperatures in the mid 90s and heat indices above 100. As our own Island heated up, much of the western half of the continent was also inflicted by a "heat dome," shattering historical temperature records and directly being responsible for the deaths of hundreds of people between the two countries. Simultaneously, the West is also facing an unprecedented drought, with reservoir and aquifer levels at all time lows. Water is being turned off, crops are no longer being irrigated, and species are going extinct. The dry conditions have also sparked the perfect storm for wildfires, with entire towns being engulfed within a matter of hours.
It is becoming painfully obvious with each passing year, as the records continue to be broken, that the Earth is warming. Each season brings new extreme weather along with it. Polar Vortexes, Heat Domes, Superstorm Hurricanes, Derecho Storms, Tornadoes, Flooding, and Hail, just to name a few. This year we experienced a dry spring on Long Island, with temperatures bouncing between cool nights and warmer-than-normal day time temperatures. Many observed these irregularities first hand, as the natural world around us tried to adapt. Many of our native plants have been observed to be "acting strange" or maturing faster than normal, or in my case needing irrigation when they never have before. You might think, "we live in the North East, we have plenty of rainfall," but looking at the map above eastern Long Island and much of New England is expected to experience long-term drought over the coming years. We need to plan now for an unstable future, and that includes our gardens.
You may be wondering how your home garden can help with climate change. The answer is native plants! Many of you may know that native plants are touted for their "drought tolerance" and "low-maintenance" qualities but there is so much more. It is always best to use ecotypical plants to our region as these plants contain genetic material that has evolved within our local environment. Exposed to environmental factors for millennia, these genes are coded for survival under the harshest local extremes. These plants will be most adaptable to climate change, whether it is drought, extreme cold, floods, or pests - genetically adapted species will always fair better than an outside genepool. This is also why it is important to avoid cultivated varieties (cultivars) as this limits the genetic diversity of not only your own plantings but also the local wild populations as well.
Maintenance is also a big key to how our native gardens will help mitigate climate change. Purely by the lack of using fossil fuels in a weekly maintenance protocol we are saving upwards of 18 pounds of carbon emissions from being released into the atmosphere each week - the biggest component of greenhouses gasses leading to climate change. But native plant gardens go much further and sequester carbon within the soil or the plant tissues themselves and remove it from the atmosphere all together. This can be said whether you are planting a forest garden full of trees or a pocket prairie whose roots extend dozens of feet below the soil surface. By mulching our leaves, stems, and old shoots, we further sequester carbon and build soil as this detritus is broken down by decomposers and turned into fresh Earth.
Native gardens also help conserve the most important natural resource there is - water. Our irrigation on Long Island is mostly supplied by treated drinking water which is wasted in excess to irrigate ornamental lawns. By planting the right native plant in the right place you can eliminate the need for supplemental water all together. I have personally taken an approach this year within my own gardens that if something fails due to moisture I will either see what naturally fills that void or replace it with a known species that will survive these ever-increasing temperature and moisture extremes. We are wasting and polluting our drinking water at such a high rate that soon the only answer will be to pump in water from upstate - tapping into the NYC drinking supply in a last ditch effort to ensure we have potable drinking water.
Some guidelines for how you too can design a climate-wise native garden are the following:
Plan for climate extremes not averages (e.g. minimum rainfall, minimum winter temperature, maximum projected summer temperatures)
Plant the "right plant in the right place" (e.g. don't plant water loving plants in dry soil, using trees for shade, growing green mulches, salt & flood tolerant plants along the coast)
Maintenance is key (e.g. abstain from fossil fuels, recycle biomass on your property, chop & drop mulch, compost, "leave the leaves")
Looking at the two charts above, it is obvious that the trend for New York is both increased warming and drying. Long Island in particular is unlike the rest of the country because all of our water is from ground water fed by natural rainfall. We don't have mountains and snowfall to help us persist through the year like New England or or the Western States. We have always enjoyed a moderate climate on the Island due to the ocean acting as a buffer, warming us in winter while cooling us in summer but now the global climate has been changed so drastically by human actions that these extreme weather events are beginning to endanger human lives. Unfortunately, the corporations and governments causing the bulk of the issue are not stepping up quickly enough but we as citizens and as gardeners can make a difference, and it starts with the garden right outside our doors.