Perennial agriculture, the cultivation of crop species that live longer than two years without the need for replanting each year. Perennial agriculture differs from mainstream agriculture in that it involves relatively less tilling and in some cases requires less labor and fewer pesticides, helping to maintain or even improve soil health. Perennial crops used in perennial agriculture are grown worldwide in various climates and are adapted to local environmental stressors.
The cultivation of perennial fruiting crop species is thought to have begun more than 11,000 years ago. In order to cultivate these species, human settlements had to remain stationary, a change that potentially affected the settlement patterns of some societies. Nonetheless, humans benefited from perennial fruit crops, which were less labor-intensive and had a relatively long lifespan—producing food for many years after a single planting—compared with food-producing plants that required annual planting. Over generations of artificial selection, the species were refined to produce increasingly palatable fruit. Later, the use of perennial species expanded to forage crops, such as alfalfa, and the production of timber crops to produce building materials.
According to Perennial Vegetables by Eric Toensmeier, most North American gardening and farming traditions come from Europe, where there are very few perennial crops except fruits and nuts.
Cold and temperate Eurasian agriculture centered around livestock, annual grains, and legumes, and early European settlers to North America simply brought their seeds and their cultivation methods with them, including draft animals for plowing up the soil every year.
However, in more temperate and tropical areas of the world, including much of North America, perennial root, starch and fruit crops were actively bred, selected and cultivated. These perennial crops were favored perhaps because they require less work to grow, and lacking large domesticated draft animals, only hand tools were available for farming.
Whatever the origin of our neglect of these amazing plants, we shouldn’t ignore these useful and productive foods any longer. Perennial vegetables should be much more widely available, especially because, compared to annual crops, they tend to be more nutritious, easier to grow, more ecologically beneficial, and less dependent on water and other inputs.
BENEFITS OF PERENNIAL CROPS:
PERENNIAL CROPS ARE LOW MAINTENANCE
Imagine growing vegetables that require just about the same amount of care as perennial flowers and shrubs—no annual tilling and planting. They thrive and produce abundant and nutritious crops throughout the season. Once established in the proper site and climate, perennial vegetables planted can be virtually indestructible despite neglect. Established perennials are often more resistant to pests, diseases, drought, and weeds, too.
In fact, some perennials are so good at taking care of themselves that they require frequent harvesting to prevent them from becoming weeds themselves! The ease of cultivation and high yield is arguably the best reason for growing them.
PERENNIAL CROPS EXTEND THE HARVEST
Perennial vegetables often have different seasons of availability from annuals, which provides more food throughout the year. While you are transplanting tiny annual seedlings into your vegetable garden or waiting out the mid-summer heat, many perennials are already growing strong or ready to harvest.
PERENNIAL CROPS CAN PERFORM MULTIPLE FUNCTIONS
Many perennial vegetables are also beautiful, ornamental plants that can enhance your landscape. Others can function as hedges, ground covers or erosion control for slopes. Other perennial veggies provide fertilizer to themselves and their neighboring plants by fixing nitrogen in the soil. Some can provide habitat for beneficial insects and pollinators, while others can climb trellises and provide shade for other crops.
PERENNIAL CROPS HELP BUILD SOIL
Perennial crops are simply amazing for the soil. Because they don’t need to be tilled, perennials help foster a healthy and intact soil food web, including providing habitat for a huge number of animals, fungi and other important soil life.
When well mulched, perennials improve the soil’s structure, organic matter, porosity and water-holding capacity.
Perennial vegetable gardens build soil the way nature intended by allowing the plants to naturally add more and more organic matter to the soil through the slow and steady decomposition of their leaves and roots. As they mature, they also help build topsoil and sequester atmospheric carbon.
DRAWBACKS OF PERENNIAL CROPS
Some perennial vegetables are slow to establish and may take several years to grow before they begin to yield well. (Asparagus is a good example of this.)
Like many annuals, some perennial greens become bitter once they flower, therefore they are only available very early in the season.
Some perennials have strong flavors which many Americans are unaccustomed to.
Some perennials are so low-maintenance that they can quickly become weeds and overtake your garden, or escape and naturalize in your neighborhood. (Daylilies are a good example of this.)
Perennials vegetables need to be carefully placed into a permanent place in your garden and will have to be maintained separately from your annual crops.
Perennials have special pest and disease challenges because you can’t use crop rotation to minimize problems. Once some perennials catch a disease, they often have it forever and need to be replaced.
PERENNIAL CROPS GROWN AS ANNUALS
Some perennial crops are grown as annuals because they are easier to care for that way. For example, potatoes are technically perennials, but we grow them as annuals because pests and disease pressure in North America requires us to rotate potatoes often.
On the other hand, some plants we grow as annuals do quite well as perennials, like kale.
CULTIVATING PERENNIAL CROPS
One way to incorporate perennial veggies into your garden is to expand the edges of an already established garden. Simple extend an existing garden bed by 3 or 4 feet and plant a border of perennials there.
Or, if you already grow a perennial ornamental border or foundation shrubs, consider integrating some perennial vegetables, such as sea kale or sorrel. Many have attractive leaves or flowers to enhance the landscape.
You can also take advantage of currently unused areas of your landscape, matching the conditions to the appropriate perennial. There are some perennials, like wild leeks, that will grow in shady, wet or cool conditions where you couldn’t ordinarily grow food!
If you’re already growing perennial vegetables and want to take your garden or homestead to the next level, consider Permaculture gardening.
By imitating nature’s ecosystems, this approach promotes greater partnerships between plants, soil, insects, and wildlife. In Permaculture designs, edible vegetables, herbs, fruiting shrubs and vines grow as an under-story to taller fruit and nut trees. This technique is sometimes called “layering” or building a “guild.”
Layers or Guilds need to be built over a couple of years. In the first year, plant fruit trees as the outposts around your property. That same year and over the next several years, use sheet mulching to prepare planting areas beneath the trees for the under-story plants. Sheet mulch a 2- to 3-foot-radius around each fruit tree the first year and gradually increase the mulched area as the trees grow.
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