My permaculture group is finishing our reading and discussion of The New American Landscape: Leading Voices on the Future of Sustainable Gardening (2011), ed. by Thomas Christopher, published by Timber Press.
It’s a book of essays, including two by permaculturists — Eric Toensmeier on the sustainable edible garden and Toby Hemenway on whole system garden design. Several essays explore practices that are compatible with permaculture gardening, like meadow gardens as lawn alternatives (John Greenlee and Neil Diboll), balancing natives and exotics in the garden (Rick Darke), gardening for wildlife (Doug Tallamy; see his Why Plant Native?), and managing soil health (Elaine Ingham).
Overall, as you might expect with a book written by different people on different topics, I found the book uneven.
For example, the second chapter, on SITES (Sustainable Sites Initiative), listed some jargony, rather opaque principles (“Provide regenerative systems as intergenerational equity”?) and offered two case studies, one from southern California and one from Portland, Oregon. This was not all that useful for us in northern New England.
And chapter 8, on green roofs, really wasn’t pertinent to most of us in our group, especially after reading about how much trouble they are for a residential gardener; these are probably better suited to industrial and commercial sites, and maybe densely clustered urban residences. (Although one of our group is considering a green roof for her chicken coop.)
The sections I found the most useful were the chapter on managing soil health, surprisingly, as I have read a lot about it before and usually found the topic to be as dull as it sounds; but this chapter really gave me a new appreciation for the details of the soil food web; and, less surprisingly, the chapters on welcoming wildlife to the garden and on growing a meadow instead of a lawn, and the discussion over several of the chapters (and the focus of one chapter) about the balance of natives and non-natives or exotics, which offered many pros and cons but didn’t come down to a definitive yes or no.
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What caught my attention
First and Foremost:
Plants are the only things that allow us to exist, by harnessing the sun’s energy and locking it into carbon bonds of simple sugars. “Plants enable us to eat sunshine!” They also produce the oxygen we breathe, moderate weather systems, and cycle, clean, and hold water on the land. p. 176
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Oɴ ʟᴀᴡɴs ᴀɴᴅ ᴀʟᴛᴇʀɴᴀᴛɪᴠᴇs:
* A riding mower produces the emissions of 34 average cars in the same amount of time of use. (p. 11) [Another site (pdf), not related to the book, quantifies it this way: “Mowing your lawn for one hour produces as much pollution as driving 650 miles.”]
* Grass is meant to go dormant, but we keep it (most species) artificially green. 30% of water use in the U.S. goes to residential landscape irrigation, and most of that is for the lawn, to keep grass actively growing when it should be dormant. (Kentucky bluegrass, e.g., becomes dormant over 75F unless it’s watered regularly.) p. 12
* Mass planting of trees, while they can reduce atmospheric C02, is not necessarily a green approach: “blanketing the landscape with monotonous expanses of nursery-grown trees … reduces the biodiversity of the forest flora and … obliterates the patchwork of different habitats … that many species of wildlife prefer or require.” p. 15
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* Each time another person is born, “we need to add enough plants to our ecosystem to support that person. Instead, we do the opposite: we invariably respond to each additional soul by removing more plants from the earth in order to produce more stuff for that person — the quintessential example of unsustainable behavior.” And we add 5,647 people per day in the U.S. alone. p. 177
* Manhattan’s carrying capacity is just about 0, which means that people can live there only by importing all their resources from other ecosystems. p. 181
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Oɴ ɴᴀᴛɪᴠᴇ ᴠs. ɴᴏɴ-ɴᴀᴛɪᴠᴇ:
* “Perhaps our thinking will evolve away from worrying about whether plants are native or not, and toward a valuation of how they function in today’s ecology.” p. 85
* “The most sustainable gardens are those that consume the fewest resources.” In other words, if a plant is poorly adapted to existing conditions, it doesn’t matter whether it’s native or not, it’s going to consume more resources. p. 88 [Note that 3/4 of the plants in Rick Darke’s 1.5-acre suburban yard are indigenous to his local region, many to his very local watershed, and none of the exotics he’s planted has been shown to spread.]
* Concerning perceived destruction from non-native species, “we may be mistaking change, a fundamental characteristic of life, for harm when it comes to naturalization of new species.” p. 105-106
* “If you want birds, or toads, or salamanders, or countless other species in your yard; … if you want your landscape to do something rather than just look like something, you must put the plants that support your local insects back in your yard.” Those are, for the most part, native plants. p. 184
* “No plant is native to a rooftop environment.” p. 168
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* Plant densely. If your garden requires mulch and regular weeding, you need more plants. Plant trees close enough to make a closed canopy for birds. Mass lepidoptera (moth and butterfly) larval plants together. p. 188, 190
* Insects are key. They’re the main way animals get energy from plants; insects convert plant tissues to protein for them/us. 96% of birds in the U.S. rear their young with insects, though they may eat fruit, seeds, and berries at other times. Native plants are great at attracting insects, 15x more than non-natives, and they also attract more predators for those insects, so natives won’t be defoliated but will provide birds and other predators with food more effectively than non-natives, on the whole.
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Oɴ ᴇᴅɪʙʟᴇ ɢᴀʀᴅᴇɴs:
* The average number of food miles for produce in the U.S. is 1,500 miles. Tonsemeier says, in his argument for gardens in our yards, that buying from farmer’s markets and farm stands isn’t as big an improvement as it seems, “because of the larger number of trips made by smaller vehicles.” p. 103. My response to this is: On the other hand, if I make a trip to one local farm stand (which happens to be closer to my house than the grocery) once or twice a week, while doing other errands, I think I’m still coming out ahead in terms of carbon footprint over buying everything trucked in from far away places at the supermarket. Then when you factor in the local farm stand growing most of its crops organically, and with fewer fertilizers or chemical pest controls, as well as less need where we live for irrigation, etc., I think shopping at the local farmstand is a real win.
* “[W]e can pattern our gardens after healthy wild ecosystems…. Gardeners using this technique will pick a model ecosystem to imitate, and analyze architecture (layers, density, diversity), social structures (niches, mutualisms), and succcessional dynamics using observation and research. … Finally, gardeners can analyze the niche of a model species and replace it in the garden with an analog [edible] species. p. 111 I love this copycat idea.
* A gardener may choose a tree for shade; but in nature, no tree exists only to provide shade, or fruit, or any one quality. When choosing plants, consider multiple functions. p. 216
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* “Weeds [or lack thereof] are one of the best indicators of whether you’re gardening sustainably.” If you’re overwatering, leaving soil empty, over-fertilizing, disturbing the soil, then weeds will rush in. p. 142
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* Trying to change our soil is old-school; instead, work with what you have. “Don’t fight the site.” If you have sand, plant sand-loving plants; if clay, then clay-loving. (Exception: food production areas.) p. 59. And in another chapter: “Although the traditional horticultural model has been to modify site conditions to suit the needs of desired plants, this is completely contrary to sustainable practices. … [I]nitial modifications to soil and grade, combined with subsequent needs for watering, pH adjustment, and fertilizing, all consume resources.” p. 89
* The soil food web includes bacteria, algae, fungi, protozoa, nematodes, arthropods, earthworms, insects, vertebrates, and plants. A tablespoon of productive soil holds 100 million to 1 billion bacteria. There are more than 5 million species of bacteria. p. 194
* Only two things can kill bacteria: 1. being eaten by predators; 2. rapid change that they can’t adjust to, like a sudden freeze, flood, sudden high heat, fire, a sudden loss of water or oxygen, application of toxic chemicals. Otherwise, bacteria just go dormant in unfavourable conditions and wake up when conditions are better. p. 196
* Nitrogen makes up 75% of the Earth’s atmosphere but is not useable by plants in gas form. Soil life changes nitrogen in air into ammonium (NH4) and nitrate (NO3), the two forms of nitrogen that plants can use. p. 203
* Succession is driven by the soil food web: Each habitat has a unique soil food web with a particular proportion of bacteria, fungi, and predators. This balance drives the process of succession: “In essence, the soil food web shifts over time from being dominated by bacteria to being dominated by fungi. What controls this shift is the plants themselves as they release exudates and dead plant materials….” Annuals and veggies (and many “weeds”) prefer more bacteria; perennials and trees prefer more fungi. p. 204-205
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- Phenology: the study of seasonal biological events. p.127 More on phenology here, which describes the complex relationships that make up phenology: “Phenology is a key component of life on earth. Many birds time their nesting so that eggs hatch when insects are available to feed nestlings. In turn, insect emergence is often synchronized with leafing out in their host plants. … Farmers and gardeners need to know when to plant to avoid frosts, and they need to know the schedule of plant and insect development to decide when to apply fertilizers and pesticides [or compost teas, pure neem oil sprays, kaolin clays, etc.]. Many interactions in nature depend on timing. In fact, phenology affects nearly all aspects of the environment, including the abundance, distribution, and diversity of organisms, ecosystem services, food webs, and the global cycles of water and carbon.”
- Heterotroph: That’s us! In ecology, a heterotroph is an organism that can’t produce organic substances from inorganic ones (in the case of most animals, that can’t fix carbon but use organic carbon for growth) and so has to rely on an organic source of carbon, one that has originated as part of another living organism, namely an autotroph, which are green plants, algae, and some bacteria; these can fix carbon (change carbon dioxide into an organic carbon molecule), through photosynthesis and chemosynthesis. p. 136
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- Put out water in shallow containers to attract beneficial organisms (spiders, insects, amphibians, some birds). p. 29
- Encroach further on the lawn, little by little, to grow meadow (New England Meadow plants) and fescue or carex grass (Appalachian or Pennsylvanian). And think about a native wetland mix for the ditch in the front yard. (New England Wetland Plants)
- Consider more often replacing one plant with an analog (similar requirements, shape, height, function) that’s either native to New England, edible, or both. p. 111
- For next year, plant climbing spinach (Hablitzia tamnoides). p. 121
- Increase the percentage of my plants that contribute to the local food web (more natives), and increase the amount of plant life in my yard. p. 185
- Clean up undecomposed leaves under trees and shrubs so they don’t overwinter fungal disease. p. 212
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“Obviously a garden is not the wilderness but an assembly of shapes, most of them living, that owes some share of its composition, its appearance, to human design and effort, human conventions and convenience, and the human pursuit of that elusive, indefinable harmony that we call beauty. It has a life of its own, an intricate, willful, secret life, as any gardener knows. It is only the humans in it who think of it as a garden. But a garden is a relationship, which is one of the countless reasons why it is never finished.” ― W.S. Merwin