Permaculture is becoming a larger part of our culture.

Kristin DeSouza, senior horticulturist and plant records coordinator at the New England Wild Flower Society, and Lisa Fernandes, a permaculturist in Cape Elizabeth, gave separate lectures related to the subject earlier this month at the Portland Flower Show.

DeSouza’s “Edible Native Plant Garden” uses about 80 percent natives and 20 percent non-natives, she said. She picks from a wide variety of plants, an alternative to a culture where 90 percent of our food comes from only 20 species.

And with the world’s population growing, it’s going to be impossible to feed the world with traditional methods, she says.

“Permaculture is giving us a little bit of hope,” DeSouza said.

Permaculture is a lifestyle that tries to be as independent as possible, not relying on fossil fuels and goods from a great distance away. It includes gardens with a high percentage of food-producing perennial plants — the type you plant once and keep producing food year after year.

DeSouza and Fernandes both stressed planning your home garden so that the areas you use most are closest to the kitchen door. Nearby, you should have a kitchen garden of vegetables and herbs.

In the second zone are shrubs and berries, followed by fruit and nut trees in the third zone, chickens and other animals in the fourth zone, and wilderness in zone five.

In a similar way, you have layers: a canopy of big trees, a sub-canopy of smaller trees and shrubs, then perennial plants, ground covers and vines — and all of these can produce food.

DeSouza said that in a typical garden with rows, about 40 percent of the garden space is taken up by paths for working. A common design in permaculture is keyhole gardens, which are roughly circular with a path heading into the middle, where there is another circle where the gardener can stand or kneel to work on the plot.

And you can put the keyholes together, significantly reducing the amount of space that isn’t producing food.

In these permaculture gardens, almost nothing leaves the property. All the leaves and vegetable waste are composted, and any trees and limbs that come down are chipped and used for paths or mulch.

DeSouza described creating leaf fences around the edible garden at Garden in the Woods, the Wild Flower Society’s headquarters in Framingham, Mass. She created columns using chicken wire, linked the columns for a fence, filled them with leaves, and waited for the leaves to compost, at which time she added the compost to the garden.

The Garden in the Woods also has a huge barrel they use for making compost tea, which is the garden’s prime fertilizer.

Fernandes spoke mostly about the philosophy of permaculture, while DeSouza went more with details. Fernandes had the definition I liked.

“Permaculture is a design method for creating a resilient human habitation and healthy ecosystem,” she said, noting that the word is a contraction for permanent agriculture.

DeSouza offered more in the way of practical tips.

She didn’t till the soil at her demonstration garden in Framingham but prepared it by a layering, or “lasagna,” method. She covered a lawn with cardboard and newspaper and added manure, mulch, soil and straw, which will break down and create a wonderful, rich soil.

She favors the Three Sisters, the common combination of crops that native tribes taught the pilgrims — corn, with beans climbing the corn and squash keeping the weeds down and the roots cool.

But she also promotes the Three Brothers, which uses Jerusalem artichoke (Helianthus tuberosous) as the tall plant to replace corn, groundnut (Apios americana) to replace the bean, and native ginger (Asarum canadense) to replace the squash.

She does warn that the Jerusalem artichoke can take over your entire yard if left on its own, so she suggests burying a 5-gallon pail and planting the Jerusalem artichoke in that. That not only will help keep the plant in check, it will make it easier to harvest the tubers in the fall.

DeSouza recommended a number of permanent plants. She created a damp area for cranberries. She likes Amelanchier laevis or shadbush, which is similar to blueberry, but the flavor has a hint of almond.

Purple chokeberry, or Aronia, was used by the Indians but rejected by Europeans because it was so sour they choked. DeSouza says she has left it on the tree past a few frosts and mixed it with other food to be edible.

Other fruits are blueberries, raspberries, lingonberries and native grapes, while nuts include black walnuts, northern pecans and American hazelnuts.

As an impetus for people to switch to growing food, DeSouza referred to Rosalind Creasy, one of the first renowned backyard food gardeners, who said she grew $700 worth of food one summer in a garden of 100 square feet.

CMBG LENDS AN EAR

Coastal Maine Botanical Gardens will hold a listening event from 4:30 to 6 p.m. Thursday at the Portland Public Library to discuss future projects.

Director Maureen Heffernan suggested potential new gardens; educational, conservation or research initiatives; and ideas from other gardens as possible topics, but she is open to anything.

Tom Atwell can be contacted at 791-6362 or at:

tatwell@pressherald.com