Perennials belong in your garden and on your farm, according to Eric Toensmeier, keynote speaker at NOFA/Mass Winter Conference. “We need to increase the percentage of our food that comes from perennial crops,” he said. “We should be perennializing Massachusetts agriculture,” and home gardeners can play a key role in that process, not just in planting proven perennials, but in testing and developing new varieties that farmers can then scale up.
All the major crops we eat are annuals, from arugula to zucchini, from rice to wheat to corn to beans. “There are lots of ways to make annual agriculture better, and kudos to those who are practicing no-till, cover cropping, and species diversification. The question is not doing away with annuals—that’s not going to happen—but where can we perennialize?”
Non-prime land is perfect for perennials
Perennials are crops that live for 3 or more years, including trees, shrubs, vines, and some grasses. Oaks are perennials, and so is alfalfa; apples and asparagus and raspberries and rhubarb are perennial. Perennials can fix nitrogen, provide food for people and livestock, and hold the soil, all while sequestering carbon and providing beneficial habitat and microclimates.
Typically, the per-acre yield from perennials on prime farmland cannot match that of annuals, and for good physiologic reasons—the perennial builds and maintains non-harvested tissue, such as woody roots and stems, that annuals don’t bother with. But perennials can be grown on, and thrive on, land that isn’t suited for annuals, including rocky land, hillsides, and tree-shaded borderlands.
In its potential for transforming how we grow, “Perennials for agriculture is where organic for agriculture was 40 years ago.”
In precolonial Massachusetts, agriculture was widespread, diversified, and complex.
Eric’s current research, into the history of precolonial agriculture, has begun to uncover a significant contribution of perennials to sustenance. In precolonial Massachusetts, agriculture was widespread, diversified, and complex. In the Connecticut River valley, for instance, “All of the prime farm land was being farmed, or was fallow and about to return to farmland,” and the best land was then, as today, devoted to annual crops, with the three sisters—corn, beans, and squash—integral to the annual production system. “But very little of the other, non-prime land was in annual crops.”
Farming practices were perforce organic, with tilled planting hills dispersed across an otherwise untilled field. “The combination of all this meant that people could farm for 7 to 10 years without fertilizing, then go 10 to 15 years in fallow, before returning to production.”
Strawberries were often planted after annuals, followed by other berries, tubers, and other perennials in the fallow years. Vineyards were common. Periodic burning kept unwanted growth of trees at bay. “Much of the Pioneer Valley was an open grassland for game. Beavers were more common, so wetlands were more widespread, and wild rice was abundant.”
Shovel-ready ideas, and beyond
The same mixing of perennials with crop annuals is possible today, Eric said. Perennials already function as protective systems in hedgerows around fields, providing windbreaks, habitat for beneficial insects, and food sources for pollinators. “This is shovel-ready. We don’t need to learn any more to do this. It is ready for adoption.”
Farmers in South America, “a region from which we have so much to learn,” may employ “fertilizer shrubs.” Grown between crop plants, these nitrogen-fixing perennials, called senna (Senna hebecarpa), can be cut and laid down as mulch, or turned under. These specific plants “are not a great match for Massachusetts, because of our cold winters, but the model is nonetheless a valuable one for local adaptation.
“Multi-strata agroforests, often called perennial polycultures, are also shovel ready for gardens,” Eric said. Fruit trees are the classic top-story member of this system, although others are possible.
“I am excited by silvopasture,” in which trees are added to livestock grazing areas, providing shade and other benefits. “With the right kind of trees and spacing, we can actually see increases in livestock production.” Possibilities include pollarding, in which trees are repeatedly topped at 6-7’, with the branches providing fodder for grazing livestock; and oak acorns, which, gathered by machinery, are fed to pigs to improve flavor, a system used by Walden Hill Farm in Connecticut.
There are lots of great perennial vegetables for gardeners, beyond the asparagus and rhubarb that many of us already grow. Milkweed, for instance, has eight to nine times the vitamin C as an orange, on a weight-to-weight basis. “In my vision for the future of Massachusetts, there is a lot of milkweed everywhere,” Eric said.
Cutleaf toothwort has a pungent,
peppery tase, like wasabi.
One plant Eric has begun to promote widely is cutleaf toothwort (Dentaria laciniata), a member of the mustard family whose leaves and roots are both edible, with a pungent, peppery taste, “like wasabi.”
Fireweed, mulberry leaf, bladder campion, and stinging nettle all have potential as perennial crops. “Marketability is a challenge,” and developing a wholesale market for most of these crops “is a long way out. But the garden can serve as a research and development center. As a gardener, I have the opportunity to try a lot of things, to work on developing good varieties, and then to pass the best onto farmers.”