In The Garden With KokHeong: Growing Perennial Vegetables

Los Alamos

What gardener wouldn’t like the idea of planting a vegetable once and for all and having the plant continue to produce year after year! There are a few of these perennial vegetables that do quite well here, asparagus being one of them. 

Although they can be grown from seeds, asparagus are best started from crowns. It usually takes about 2 years before the shoots can be harvested, and even then, sparingly. Asparagus crowns are available from Nurseries in early spring and late fall, which are the ideal time to plant them.  I let most of the shoots grow into ferns in the first couple of years in order to establish the root system. Asparagus is one of the first vegetables to appear in my garden, ready for harvesting in late spring through early summer. There are male and female plants. The female plants produce berries and they are more susceptible to asparagus beetles. Many commercial growers grow only the male plants, but I don’t mind having a mix, which allows me to harvest the seeds to grow new plants each year to continuously replace those that are old and less productive. Birds like to feast on the seeds in the winter, so I let them fern die and clean up only in the spring.

Another early perennial vegetable is sorrel. The young leaves are a bit sour and can be added in small quantities to salads. There are several kinds of sorrels – French Sorrel, red-veined sorrels, and Sheep’s Sorrels, to name a few. Some are more sour than others, and some are more bitter. I use them all, and harvest the leaves when they are young and less bitter.  Cream of sorrel soup is one of our family’s favorites. They can be added to salads. They produce a lot of seeds. I let some seeds on the plant to self-seed for next year, harvest some for the Seed Library, and leave some for the birds. 

Other perennial vegetables that grow well here are Jerusalem artichokes (or sun choke), rhubarb, and horseradish.  They propagate easily by sending out new shoots through their root systems so they tend to take over the entire garden if not cut back regularly. They can be divided by digging out a small section of the root system and re-potted to give away to friends or to donate to Plant Swaps and Plant Sales. 

Many herbs are perennials – tarragon, chives, rosemary, thyme, oregano, sage, lovage, garlic, and Egyptian walking onions are some of the common ones that grow well here. Others like parsley, cilantro, basil, dill, and borage are annuals but they self-seed so easily that once established, they come back year after year as if they were perennials. Rosemary, unless it’s a hardy variety, usually can’t survive a harsh winter outdoors, so it’s best to grow it in a pot and bring it inside during the winter months. I have a 20+ year-old rosemary plant, about the size of a piñon bush, that grows in my backyard on the south side of the house against a concrete wall which keeps the plant warm in the winter. 

My very favorite perennial herb is garlic chives, which is used as a vegetable in Chinese cooking. We add them to scrambled eggs for a dish that I have named “Green Eggs without Ham.” It can be an entreé or served between slices of bread like a sandwich. We also use them chopped up with ground meat as pot-sticker fillings. We cut them into inch-long segments for soups and add them to stir-fried dishes. Many Chinese chefs use them to “season” a new wok by stir-frying them until they are quite burnt, so as to “break in” the wok. The burnt garlic chives can be composted. Garlic chives’ flower buds are especially valued and they sell for three times as much in Asian Markets as their leaves. When they are covered with an upturned pot or other containers to keep the sun off as they grow, they turn a golden yellow in color and they are called Golden Garlic Chives. These taste a lot sweeter than the green ones and are especially sought after by Chinese chefs for special dishes. Their clusters of tiny white flowers are attractive to bees and can also be harvested for making relishes and pesto. The seeds themselves can be pounded into a paste with olive oil  into a tangy paste that can be served over crackers or toasts.  

Egyptian walking onions are named for the way they propagate. They don’t produce large bulbs underground like regular onions, but produce long stalks with small shallot-sized bulbils at the tips. If left alone, the cluster of bulbils get so heavy that it droops over and the bulbils develop roots  in the soil to grow a second cluster of plants about a foot away from the mother plant. This continues for the 3rd and 4th clusters so it looks like the onions “walk”. I use Egyptian onions in 3 ways – the young leaves like scallions, the larger of the bulbs like shallots, and the scapes that emerge from the bulbils like onion-flavored asparagus before they toughen into hollow stems. 

Some annual vegetables also behave like perennials by self-seeding if allowed to go to seed, such as arugula, lettuce, kale, spinach, mustard greens, Swiss chards, and other members of the cabbage family. Carrots and celeries will produce flower heads and seeds the second year if unharvested the first year. After I’ve harvested all that I can use from my Chinese cabbages, broccoli, and cauliflowers in the fall, instead of pulling them out by the roots, I cut the plants down to a few inches above the ground, leaving a couple of nodes. Should we have a mild winter that year, most of them would survive and produce an early crop of greens from the nodes the next spring, with even some early flowers for the bees! 

Another common perennial vegetable is artichoke and its close cousin, the cardoon, which is used in Italian cooking. Unlike artichokes, cardoons are grown not for their flowers but for their long stems, which look like celery. The stems are wrapped in brown paper a week or so before harvesting so that they stay pale and tender. The entire plant is then cut down, the spiky leaves removed, and the stalks sold in supermarkets. I plant them both as ornamentals for their purple flowers to attract pollinators. 

There are a few perennial vegetables that grow in ponds, watercress being one of my favorites. Not only are they able to withstand a mild winter, they readily self-seed. Since pond water may be contaminated with salmonella bacteria, I would wash the watercress very carefully and only use them fully cooked in soups and stir-fried dishes rather than raw in salads.

Given all these choices of perennial (and self-seeding annual) vegetables, what would you grow?