There are many perennial vegetables that we can grow in Portland. (For beginning gardeners, perennials are plants that return year after year.) It's a great idea to get some of these established in your kitchen garden. With very little work they will give you a huge harvest over the years.
Artichoke
Artichokes are thistles! We eat the bud before the flower opens. They are hardy to 15 degrees in winter, so they are a great perennial veggie for the Pacific-Northwest. Have a bit of patience, you’ll usually have to wait until the second year an artichoke plant is in the ground before it will flower. If you let some of your artichokes go to flower, the pollinators will quite enjoy it.
Asparagus
Asparagus requires even more patience than artichokes. If you install a perennial asparagus bed, you can expect to reap your first harvest in 3-4 years. Although it takes them a while to establish, it’s well worth the wait!
Asparagus appreciates being in its own dedicated, undisturbed bed. It doesn’t do well with competition or compaction. The first couple of years the roots will send up thin shoots. Let these unfurl, enjoy their fern-like texture, and they will send food to the roots. Weed often by hand in order not to disturb the asparagus roots. Once properly established, an asparagus bed will produce spears for decades.
Bamboo
Bamboo is more often thought of in the West as an ornamental screen plant, but the shoots of some varieties are quite tasty! Harvesting also slows their spread. Each young cane you harvest, is one less cane that will grow to maturity. The soft, white interior of young canes is the edible part. Please research preparation methods before eating, some varieties need to be boiled for safety.
Cardoon
Related to artichoke, cardoon is also a perennial vegetable. When you harvest cardoon you will collect the stalks rather than the flower bud. Little-known in the United States, it’s a traditionally used vegetable in Northern Italian cuisine, such as in a dish called Bagna càuda. Stalks are high in potassium, calcium and iron.
Daylillies
Most people think of daylillies as a prolific and beautiful ornamental plant, but they are also a perennial edible! Of course, if you plan to eat them, please make sure you are planting Hemerocallis, not the lilies you see in florists’ shops. The shoots are edible in spring, when they are less than 8 inches tall. You can also eat the flower buds, whole flowers, stalks, and root tubers. Hemerocallis fulva is one of the best varieties for eating, though many more are also edible.
Garlic
Garlic is most often grown as an annual, but with the right gardening know-how hardneck garlic can be grown as a perennial. The experience might shake up your expectations of this plant.
If you are aiming to grow it perennially, you will change what you harvest. Instead of collecting the large cloves of the terrestrial bulb, focus instead on garlic greens, scapes, and bulbils.
Greens are just what they sound like - the green leaves that first appear in spring. Scapes are garlic flower buds. Bulbils are small, round garlic cloves that form at the top of the plant if the scapes are allowed to mature. They often have a mellower flavor than the large clove. If you’re excited about eating them, try growing Rocambole garlic. Rocambole gets 10-20 large bulbils, while other varieties get many more, they are much smaller.
Extra bulbils can be planted to grow new plants, but it will take two to three years for them to form large cloves.
Kale
Although kale is often grown as an annual, it’s really a perennial plant. During our mild winters it will survive, producing seed that is often hardier and more suited to our climate. (Use this seed to replant into different beds, therefore avoiding pest build-up.) Growing them in a protected micro-climate can also help plants get through the harshest winters.
Rhubarb
Rhubarb is wonderfully suited to growing in the Pacific-Northwest. Make sure to give this plant room to grow, it can get up to three and a half feet tall and wide! The red stalks are used to make pies, jams, and in applesauce. Be careful not to eat the leaves, as they contain high concentrations of oxalic acid.
Scarlet Runner Beans
These beans have such colorful flowers, they are often grown as annual ornamentals, but they are actually perennial and edible! Given proper support and care, these plants can live up to 20 years. Rich in vitamins and minerals such as Molybdenum and Copper.
Sea Kale
Little-known, but wonderful edible. Plants are edible from their first purple shoots, to long stalks, flower buds, and small pea-like fruits at the end of the season.
Sorrel
Sorrel is a tasty green with a zesty lemon flavor. It’s best used cooked due to its high oxalis acid content. For extra beauty in the garden, try the red-veined variety. French sorrel has been selected for lower oxalis acid content. Vitamins in sorrel include vitamin A, vitamin C, and folate.
We recommend removing seed-heads after flowering, otherwise it tends to freely self-sew.
Sunchokes
Native to the Eastern United States, sunchokes, which also go by the name Jerusalem artichoke, are an underutilized crop that are perfectly suited for the Pacific-Northwest. For those who aren’t familiar, they are a root crop that grow much like potatoes but are said to taste like artichoke. Sunchokes have an added bonus: they are in the same genus as the common sunflower, so their flower is beautiful! The seeds they produce are small, but much loved by birds.
With very little work you can have a cheery sunchoke patch that will provide you with a consistent crop year after year. They are so easy to grow, in fact, that you might want to consider installing them with a growth barrier or in a container so that they don’t take over more of your garden than you’d like.
Sunchokes are a source of protein, fiber, potassium, and iron, while having no significant amounts of fat.
Walking onions
Walking onions are called this because, like hardneck garlic, they form bulbils when allowed to go to flower. If left to their own devices, the bulbils will get top-heavy, fall over, and plant themselves -- over time, walking across the garden.
What else?
And these are just veggies… in addition, there are many options for perennial fruit and herbs in the Pacific-Northwest.
