Natives – A Moving Target?

Will the wild orchids in my woods survive the changes of the next half century?


There was a certain irony in the timing, given America’s withdrawal from the Paris Climate Agreement.  Still, last week was the time when a group of Master Gardeners had asked me to give them a lecture about the possible effects on gardening of global climate change – and how gardeners can do their part to meet this challenge.  Because my wife is a geologist who studies long-term climate change, I had expert help with the scientific aspects of this issue.  Different climate-modelers present different scenarios of what is likely to happen as our current century unwinds, but virtually all agree that unless we kick our addiction to fossil fuels, our climate will grow significantly hotter by the end of this century.  Indeed, the way things are going now, it looks as if by 2100 summers in upstate New York will be as warm as those of present day South Carolina.

Obviously, this sort of transformative change will have many effects on gardening.  One point that particularly troubles me is the impact that it will have on what plants will flourish naturally in our region.  Like so many other gardeners, I support the use of native plants – that’s a fundamental part of the message of Garden Revolution, the book I wrote with landscape designer Larry Weaner.  But what will be native when the trees we are planting now mature?  By century’s end, even if we moderate our use of fossil fuels, suitable habitat for our current forest types are predicted to have drifted 350 miles northward.


Changes are already underway: already we are seeing forests stressed by the northward movement of what were formerly southern pests such as the southern pine beetle, which was formerly confined to the Southeast but which is now moving into southern New England.  Many kinds of wildlife are also stressed by the change in the seasons.  The earlier arrival of spring is prompting the earlier emergence of many insects; animals higher up the food change such as birds have typically adjusted less to climate change with the result that they are hatching chicks at times when caterpillars and other customary foods for the nestlings have passed.

Other than the obvious point that gardeners must do their part to moderate climate change – for example, minimize the use of dirty two-stroke gasoline engines and the application of greenhouse-gas-generating synthetic nitrates – the answer to our changing ecosystems is beyond me.  Given that Americans in particular seem loath to address their addiction to fossil fuels, perhaps the most realistic response is to accept that our current native plant communities are on their way out, or at least on their way north.


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My father was a compulsive tree planter, but it was my mother who taught me the finer points of gardening.

Her homeschooling was followed by two years in the New York Botanical Garden’s School of Professional Horticulture, and then ten years as horticulturist at an Olmsted Brothers designed estate on the Hudson River Palisades.

I’ve worked as a horticultural journalist for 35 years, contributing to publications ranging from Martha Stewart Living to the Journal of the Royal Horticultural Society and The New York Times.  My most recent book is Nature Into Art: The Gardens of Wave Hill, which is a tour of the lessons to be learned from that great public garden.  I’m currently focusing on my new podcast (at which features weekly interviews with leaders of environmentally-informed gardening.

My special enthusiasms include sustainable gardening, especially sustainable lawns;  heirloom chicken breeds; and recreating vintage New England hard ciders.


Contact Tom by email


  1. Excellent post. This is something we gardeners really need to think about, especially when planting long-lived trees and shrubs. What does native mean when the plants that lived here 50 years ago won’t be able to survive here 50 years into the future?

  2. So will the lady slippers survive? Cornus canadensis and painted trillium?
    Will Vermont lose its maple sugar business?

    • Actually, Vermont is projected to lose its maple sugar business as well as its ski resorts.

  3. The migration upward in elevation of non-native invasive plant species was nearly five times greater than that of the flora overall, and even more when compared to localized endemic plants.

    Combined with the much more extensive movement of introduced species across the state, endemic species may face not just the ongoing challenge presented by a shifting climate, but two compounding challenges: climate and competition from introduced species.

    In part, the horticulture industry is to blame. By 1994, 235 nonnative woody species had become naturalized in North America; 85 percent of these were introduced by the landscape trade for aesthetic or functional purposes, such as erosion control. Of the 300 invasive plant species (all types) in the U.S. (except for Hawaii), 50 percent of them were imported for horticultural purposes.

    How can a native compete with that?

    In Maryland, mitigation for tree loss is required. Below is a photo at the Agricultural Research Service here in Beltsville, Maryland. The ARS performs much needed agricultural research. (Well, with the Agriculture cutbacks, one third of these sites will close across the U.S.) These fields used to be mowed occasionally. Native trees were planted as a mitigation planting as you can see. But, with the sequester, mowing staff was cut by 80%. So, you now have a field of native trees, on unmowed grounds, many now dead, overgrown with non-native flora which is now spreading throughout the 7,000 acre site. Bird numbers dwindled because of the overgrowth, which means less healthy natives in the surrounding forest.

    So invasive species are on the march and they march fast.
    We need to:
    1. Sell more natives.
    2. Care for the sites where they are planted.

  4. Interestingly, I’ve read that recent research shows species of plants and animals aren’t moving north as expected with climate change, but rather the ranges of species that adapt well are growing larger (imagine the range of livability spreading horizontally rather than vertically on the continent), while the range of unadaptable species are growing smaller (rather than broad ranges, the areas where they live are becoming islands or pockets).

  5. What a stimulating thought you shared in there. We, gardeners must understand this and how we can consider our plants as natives ( Would be thinking deeper about it but I think the comment on top is right, species of plants are not moving, rather they are adapting to the changes that we, humans are also experiencing.

  6. Great post. A few favorites of mine here in Fort Worth Texas area are:

    Liatris elegans (Blazing star)
    Hibiscus coccineus (Scarlet rose-mallow)
    Erythrina herbacea (Coralbean)

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