At Brooklyn Bridge Park, horticulturalist Rebecca McMackin had to think fast to repair the damage after Superstorm Sandy churned ashore in New York City in 2012. Floods, saltwater, and waterfront devastation forced her and her small staff to come up with radical ideas for a healthier, more resilient landscape to stand up to our world’s rapidly changing climate.
For centuries gardeners have created landscapes by adapting their sites to the plants they have chosen to cultivate. Now horticulture innovators are questioning the age-old methods. At Brooklyn Bridge Park, landscape architect Michael Van Valkenburgh designed the the narrow 85-acre site built on piers on the East River shoreline to be resilient to a changing environment, making it possible for McMackin and her crew to come up with a plan to repair the damage and protect it from future floods.
A garden designer who also heads Mantis Plant Works in Brooklyn, McMackin holds advanced degrees in landscape design and environmental biology and is uniquely qualified as both a scientist and a hands-on gardener to develop strategies to combat climate change. The same ideas can work in your garden and mine.
Here are nine ideas from McMackin, who is now the park’s director of horticulture, on how gardeners can make a difference.
Accept your ecosystem.
“The right plant for the right spot” is one of the traditional maxims of successful gardening, but McMackin would amend that to “the right plant for the right ecosystem.” Think of your garden as an environment where living organisms such as plants, birds, insects, and other animals need to coexist happily with other elements such as the soil (have you tested it?) and the weather (what is the annual range in temperature, and how much wind, rain, and snow do you get?).
With weather unpredictable and climate in flux, it is important to choose plants that want to live where you want to plant them. As conditions evolve, the plants will be better able to adapt.
Investigate your soil.
Analyze your ecosystem thoroughly to determine the conditions of soil, water, sun, and wind. If you are designing a new garden, conduct a ribbon test for soil texture, a percolation test for drainage, and consult online charts for average rainfall amounts in your area. In an existing garden, look at the plants (even weeds) that are growing happily and determine what conditions are helping them thrive. Any new plants you introduce should also be comfortable with those same requirements.
Accept your soil.
Analyze your soil and then basically accept it as is. If your soil is extremely compacted, you might want to explore methods of decompaction, but in most cases simply planting enough different plants with vigorous root systems to penetrate various soil layers can, over time, create a looser, more hospitable plant environment. What McMackin doesn’t advise is the old practice of hauling in big heavy bags of compost, humus, and other soil additives. She believes that plants should be left alone to go about creating the habitat they want to live in. For instance, she notes that oaks and pines drop acorns and needles in an attempt to acidify their soil.
Let plants care for themselves.
As McMackin says, “gardeners love to fuss” over their plants. But placing plants in environments where they have the light, soil, moisture, and nutrients they need eliminates the necessity for a lot of ongoing maintenance. Plants that are comfortable where they are tend to be stronger and more resilient and require less staking, watering, feeding, and pest management. The goal of the gardener, says McMackin, is to get plants to be more independent by matching them well to their habitat.
Be an ecological gardener.
While organic gardening replaces chemical fertilizers and insecticides with natural methods, ecological gardening goes further by allowing a garden to become more self-sufficient and home to a whole system of mutually dependent organisms. For instance, McMackin notes that the organic gardener rakes up leaves in the fall, composts them, and then adds them back to the soil. The ecological gardener simply allows the leaves to stay on the ground to decompose and feed the soil all on their own.
Says McMackin, “Deciduous trees are not throwing their leaves away when they drop them in the fall. They are laying them on top of their roots for protection and building the soil they want to live in.” She adds that beneficial insects overwinter in the leaf layer, which also provides crucial habitats for small mammals and birds.
Pick trees for porosity.
When you are considering a tree for your garden, it is wise to determine its water needs. If your site lacks irrigation, you will probably want to plant a tree that will take up and store a lot of moisture in the spring to help it get through periods of summer heat and drought. Trees in this category are known as “ring porous” and include such hardwoods as oaks, hickory, black locust, and sassafras. If, however, your site can provide an adequate supply of water throughout the year, you could choose a “diffuse porous” tree such as American beech, sycamore, or maple.
Plant in autumn.
McMackin is a strong advocate for planting perennials in the fall and believes the idea of spring planting may be something American gardeners copied from British gardeners who work in a much different, milder climate. Plants installed in the autumn have a longer timeline to establish themselves before the stress of summer heat arrives. While you have to monitor the plants for heaving in the freeze-thaw cycle, you will need to spend less time watering. McMackin says plugs in particular benefit from the extra time in the ground.
Wait out the bugs.
In Brooklyn Bridge Park, McMackin says her philosophy is to wait out insect infestations. She points out that, in the eyes of insects, gardens are basically vast buffets of food so it is natural that your plants will have to endure some nibbling. She advises closely observing your garden to see if you have predators such as ladybugs or lacewings in residence. In many cases these beneficial insects will help to curb infestations and should be actively encouraged.
Delay fall cleanup.
McMackin believes that the once-traditional fall cleanup is an outdated procedure. She cautions that when you remove dead plant material, you wipe out the good biological helpers that your garden needs. For example, by cutting down plants with hollow stems you risk harming pollinators such as bees, which often overwinter inside them. At Brooklyn Bridge Park, the policy is to delay the cutback until early spring; do it after a couple of 50-to-55-degree days. The warm temperatures will give solitary bees a chance to become active and leave the shelter of the stalks.
These new strategies react to a changing climate, but they also follow nature’s practices closely and honor the earth’s natural processes. We as gardeners may ultimately have less labor to do, and it is possible we will be rewarded with healthier plants and a deeper respect for what nature can do on her own.
Wondering what else gardeners can do in the face of climate change? See our curated Garden Design 101 guides and eat local with tips from our Edible Gardens 101: A Field Guide to Planting, Care & Design. See more ideas:
- Unconventional Wisdom: 8 Revolutionary Ideas for Your Garden from Thomas Rainer
- 10 New Year’s Resolutions for the Gardener
- Hike of the Week: Brooklyn Bridge Park
- Global Warming: 10 Gardening Ideas to Counter Climate Change
- Global Warming: An App to Track Climate Change
- Landscaping Ideas: 16 Simple Solutions for Sustainability