Plant Perennials For the Garden that Keeps on Giving
Turn your yard into a mini “food forest” and reap benefits far beyond the crop on your plate.
STORY BY BILL THORNESS
It is surely the biggest flower that you’ll ever eat, and the only one with a heart. But if you’re not careful, its spiky petals can prick your fingers, and you might be unpleasantly surprised by a squirming, pincered earwig climbing out of the bud. This mystery vegetable is, of course, the artichoke, and it’s one of more than a dozen perennial vegetables that can be easily grown to provide food year after year with much less care than anything coming out of your annual vegetable patch.
Artichokes form a striking hedge along one border of my garden, and their blue-green leaves gets me through the winter months with warm reminders of tasty harvests. In early spring, the many-lobed leaves arc lustily toward the sidewalk, their dense foliage hiding buds that shoot skyward on stalks from the center, offering up fist-sized buds by mid-spring that predate many other crops. When I start harvesting artichokes, I know that other favorites aren’t far behind.
The artichoke is one of the best arguments for growing perennial vegetables: it’s attractive, low-maintenance, and one of those gifts that just keeps on giving. This year, consider turning some yard space over to such reliable edibles.
What’s this now?
Many new gardeners turn to perennial vegetables almost as an afterthought, perhaps stumbling over them when clamoring for the annual tomato starts or potted herbs. The discovery can produce almost a “eureka” moment: You mean I can just plant once and harvest again and again?
Well, yes, with a little planning and patience. Perennial vegetables are defined as plants that grow for three or more years and provide an edible harvest year after year. For some plants, it takes a couple of seasons or years before they begin to produce.
We think of them as “the herbaceous species we usually call perennials,” says Eric Toensmeier in “Perennial Vegetables” (Chelsea Green, 2007), but the category can include “trees, bulbs, shrubs, cacti, bamboos, grasses, and vines.” The topic’s recognized guru lists more than 100 plants in that book, but many of them are more suited to warmer environments than our cool maritime climate. Even so, I’ve tried more than a dozen that thrive here, and some have become well-loved parts of my diet.
A few, like artichokes, are uber-familiar. Asparagus is a prize, rhubarb an old reliable. In the vast brassica genus there are a couple: tree collards and perennial kale. Sunchoke (aka Jerusalem artichoke) is prolific to the point of weediness here, and stinging nettles are often gathered from their wild patches rather than cultivated in the home garden. Garlic chives provide the spicy zing to the field, as do other alliums like potato onions.
Plenty of bennies
In essence, you can turn your yard into a mini “food forest” and reap benefits far beyond the crop on your plate. Perennial vegetables extend your harvest season, especially in spring. Blended in with your ornamental plants, they add variety, and permaculture folks would point out that a landscape which includes these crops will enhance your garden ecosystem.
Just like any new garden addition, consider the plant’s needs before purchasing: sunlight, water, and soil conditions. Many want full sun and regular water, but some can tolerate shade or neglect — or even thrive in a boggy location. The best patch of sunchokes I’ve seen, sprouted from a marshy mess under a spreading tree. Dandelion (yes, I know, but …) will erupt from even the most unloved soil.
It’s good to consider soil fertility before planting, however, because the plant will be in place a long time, unlike the annual vegetable. That said, some perennial vegetables can help build the soil, pulling in nitrogen or sending down deep roots to mine for nutrients.
Once established, many of these crops don’t need a lot of added fertilizer. To enhance the soil and keep your perennials thriving, a regular dose of compost to add organic matter and hold water may be all that you need to do.
Perhaps most importantly, perennials offer sustenance to a host of other species in our gardens. Because the soil is not turned over regularly (as is our vegetable garden), the complex soil food web can take root and flourish. The plant’s flowers, some of which show up earlier in the spring than many other species, provide valued nectar and pollen sources to beneficial insects. These are plants that can truly feed the world.
Try some of these
Here are some of my favorite perennial vegetables, and ones that are proven to grow well in our climate. These edibles can be grouped by the segment of the plant that you eat: buds, leaves, stems, shoots, and underground parts (bulbs, roots, and tubers).
Buds and leaves: artichoke, dandelion, New Zealand spinach, perennial kale, tree collards, sorrel, and stinging nettle. New Zealand spinach can be a groundcover, of which the young leaves are quickly cooked. Perennial kale can be a small bush and is well-suited to growing in pots. Tree collards can be rangy and messy, and only their young new leaves will be desirable. Sorrel is an aromatic leafy green on a compact plant. Dandelion leaves are best when young, and extremely nutritious stinging nettles must be carefully handled but lose their prickliness when cooked.
Stems and shoots: cardoon, rhubarb, bamboo, garlic chives, and sea kale. Cardoon is an artichoke relative with meaty, edible stalks. Bamboo can be invasive, but you can get revenge by cutting its shoots when just inches long, then peel and boil. Garlic chives provide both tender young shoots and spicier purple flower heads. Sea kale is a brassica that produces spring shoots (best when blanched) and buds from a mass of leaves, which are also edible.
Underground parts (bulbs, roots, and tubers): sunchokes, yacon, oca, potato onions, Welsh onions. Sunchokes can be aggressive, so should be dug and contained regularly. Yacon and oca, two tuberous foods of the Andes, are grown as replantable annuals (similar to potatoes) in our climate, although they are perennials elsewhere. Yacon tubers are sweet, while oca is more mild and potato-like. Yacon and sunchokes both contain inulin, causing gaseous indigestion in some people. Potato onions also are replantable annuals and multiply underground like shallots. Welsh onions are also known as scallions; if a part of the clump is replanted after harvest, it will spread into a new clump.
As usual, so many choices, so little garden space. But if you consider your garden in terms of years, not months, the giant-flowered artichoke may be well worth the real estate.
Bill Thorness, author of Cool Season Gardener, grows edibles in Seattle and bravely practices catch-and-release of the harmless earwig.