Plants come in two varieties: annuals, which will survive for a season, and perennials, which should come back year after year. Many of the plants in your vegetable garden, from carrots to tomatoes, are annuals, but you can grow quite a lot of perennial crops too.
In my book, growing your own perennial food forest—an enduring source of nourishment— of perennials is a sign of a true gardener. Here are all the edible perennial plants I recommend adding to your yard. (Note: Plants are all susceptible to weather, so which plants will "perennialize" is dependent on the USDA planting zone you live in. In some places with harsh winters, artichokes are treated as annuals, for instance. Talk to someone at your local garden center to learn what perennial plants will thrive in your zone.)
Berries
Most berry plants are perennials, including strawberries (in most ones). Planting a diversity of both June bearing (that is, plants that fruit in June) and ever bearing (plants that fruit all summer) strawberries mean you should have a full summer of berries. But strawberries aren’t the only game in town: Blueberries are outstanding shrubs that thrive in full sun or partial shade, and don’t require too much water. There are hundreds of varieties, and if you plant a mix of early, mid, and late varieties, you’ll have blueberries from June to August.
Other berries grow on bushes as well, from currants, goji berries, thimbleberries, gooseberry, honeyberry, salmonberry, huckleberry, and more. Elderberries grow on shrubs that can reach 30 feet tall within a few years. Then there are all the cane-based berries, like raspberry, blackberry, boysenberry, marionberry, loganberry and tayberries; these plants need support, like a trellis, but will grow prolifically and spread easily (with a little care, you can keep them in check).
Fruit and nut trees
Well cared-for Apple and pear trees will last for generations, providing harvests year after year. The same is true of stone fruits like apricot, peach, cherry, and nectarine. I’d can't imagine my garden without a fig tree in it—although like elderberry, they can grow to immense heights if you don't keep them under control.
Within each type of fruit are many varieties that provide variance in terms of taste and timing of harvest. The same is true for nut trees—including almonds, walnuts, pecans, filberts, and other nuts. These trees can also provide a canopy over other parts of your garden, benefitting plants that thrive in the shade.
Asparagus
An absolutely fascinating vegetable, asparagus is generally planted as a root in a ditch; each spring, it will send up the shoots we recognize as asparagus. (While you can grow asparagus from seed, it takes a few years for the spears to be ready to be plucked, so most people purchase crowns instead.) Watching my asparagus bed reappear each April is a delight; the crowns keep coming back, and an asparagus plant can live for 15-20 years.
Rhubarb
A funny looking plant prized for its stalks, rather than its leaves or fruit, rhubarb grows from a rhizome. The stalks will have a green-red color, but you can blanche them stalks early in the growing process to get those prized cherry red stalks. Rhubarb is harvestable from spring through early fall, and is slow to spread. It’s an ideal plant to put under trees (in the understory), as the less sunlight, the brighter red it will be.
Horseradish
Unlike rhubarb, horseradish is a taproot, and spreads quickly via a network of underground roots. Every spring it will shoot up tall green leaves which can also be eaten. At any time, you can dig up one of the roots to harvest it. As horseradish loses its spice the moment you cut into it, having fresh horseradish at your disposal is a real delight. You can even replant part of a root; it should take hold and produce more plants. Like rhubarb, horseradish is a great plant for an understory.
Artichokes
I dreamed of a garden full of artichokes my whole life, and now that I have one, it is as wonderful as I imagined. Artichokes slumber all winter, but come early spring, they come to life, growing as tall as seven feet, with sprawling silver-grey leaves. Shoots then appear, and at the end of each shoot, an artichoke. Each plant will produce a large artichoke, and then each successive one will be a bit smaller. Artichokes you don’t pick will open and flower into magnificent purple bee havens. They make a spectacular border plant when clustered together.
Fennel
You can’t kill fennel. I’ve tried. And it can’t be grown with anything else, as it will keep other plants from flourishing. Even worse, it grows via a taproot and spreads easily. So why do you grow it? Because fresh fennel is lovely, and when fennel is allowed to go to seed, it produces bright yellow pollen you can harvest to use in cooking (and to save your own fennel seeds). Bees also adore fennel.
Egyptian walking onions
The most fantastical vegetable there ever was, walking onions throw up a singular green stalk from the onion bulb in the soil. At the end of the stalk, three tiny onions will grow, flopping around in the air, until they are heavy enough to lean the plant over, where they will implant themselves in the soil and start over—hence the “walking” name. You can harvest either the bulb in the soil or the ones at the top of the plant. (I give my walking onions more space than I should because when I’m waiting for other things to sprout or fruit in late May-early June , the architecture of the walking onions keeps me amused.)
Saffron
The red stamens used to delicately flavor and color rice are actually from crocuses. You can buy them as bulbs and watch them flower, and then harvest the red stamens for your own saffron bounty. It’s important to put these bulbs where you can watch and access them so you don't miss your shot at a harvest, so planting boxes are a perfect choice.
Herbs
Perennial herbs are the ultimate edible perennial staple. Bay leaves, rosemary, lavender, sage, mint, thyme and plenty more can be grown year round as hardy shrubs. In some cases, you can successfully perennialize herbs like parsley and dill, which means that they continually seed themselves and come back on their own, though this requires continually seeding in the same place for a few years until they take hold, and a bit of luck.
Ramps
A relatively recent development, you can now purchase ethically farmed ramp bulbs specifically to grow in your own garden (I usually find them on Etsy). This means you'll have your very own ramp patch that will grow every year (if you're careful about harvesting them). Ramps need dappled light and a lot of moisture, so grow them alongside mushrooms.
Mushrooms
There are a multitude of ways to grow mushrooms, whether in buckets, on logs, or just by throwing spawn down on your wood chipped pathways. Having access to mushrooms, which flush in waves, is economical, if nothing else, and there’s something magical about going outside and find new shiitakes or wine cap mushrooms in my yard. Mushrooms require dappled light, which means you have to make them an understory plant.
Other plants that may perennialize
Other edible plants can become perennials if you can get them into a cycle of reseeding themselves, including potatoes and sweet potatoes—if you leave some small potatoes behind when harvesting, you’ll find the bed will regenerate come spring. Radicchio will often find a way to come back year to year, and onions may perennialize if you allow them to go seed, as might celery. I've had less luck with broccoli species that are claimed to return each year.