How to grow edible perennials

(Chelsea Conrad / Washington Post illustration)

My backyard is a cemetery, filled with sad reminders of failed edible perennials. There is an abandoned space along the western fence that was an attempt at a strawberry bed. A few meters away is a bit of dead space where I failed to grow a rhubarb spot. Out front in front of our stone walkway, a bit of the sunny side yard disappears, which I thought would be the perfect spot for a raspberry berry. I was mistaken.

These plants are supposed to be set-it-and-forget-it-types – easy to maintain and durable. Although I have a green thumb when it comes to my vegetable and herb gardens, edible perennials are clearly my weak point. My disappointment runs deep. I have a vision of a farm surrounded by reliable producers, reliable sources of fruits and vegetables all year round to help keep my cooking fresh and interesting.

Determined to finally bring my dream to life, I turned to four gardening experts to gain their insights into what options are best for the DC region, and growing tips to ensure success. Armed with this knowledge, I plan to turn my backyard cemetery into a lively collection of edible perennials – and so can you.

“When the zombie apocalypse comes, this will be the most reliable vegetable in your garden,” says Kathy Jentz, editor of Washington Gardener magazine.

The tubers produce lush, which is both an advantage and a disadvantage. Left to itself, sunchokes can take over your garden. To avoid this, plant them in a separate bed, preferably away from your others, perhaps along a property boundary. Insert a root barrier into the soil that extends three feet deep along the edges of the bed. A place that receives full sun is best. Unless there are drought-like conditions, no irrigation is required. Plan to harvest in October, and then cover the patch with mulch or hay for the winter.

“Just put it in the ground and get out of the way,” says Lincoln Smith, founder of Forested, a forest garden design firm. “It’s a perennial for dummies.”

Plant horseradish roots in a place that receives full sun. They must be in a separate bed; the burning herb will run amok and take over everything else that grows nearby. Prepare the soil for planting by cultivating the soil about 10 centimeters deep, removing stones and mixing in compost. Horseradish can be harvested all year round, except when the soil is frozen.

If you have a sweet tooth and do not want to do a lot of work, raspberries are a safe bet, says Meredith Sheperd, founder of Love & Carrots, a garden design and installation company. “They self-pollinate, they produce the first year, and they produce closely.”

Choose a 3 x 10 foot section of your garden that receives at least four to five hours of sun a day, although six to eight hours is ideal. (My own raspberries failed because they did not have enough space or light.) The brambles will naturally fill the space with time without any extra attention. Expect to harvest them all summer. In general, raspberries are very low maintenance; just cut them back in the fall.

To be successful with these juicy berries, you need to find a place in your garden that gets at least eight hours of sun a day. Then consider how much space you can set aside for them. “Strawberry beds are gaining momentum,” said Dominique Charles, founder of Plots and Pans, which specializes in edible gardens and landscapes. “So you need a lot of space or a way to contain them, such as raised beds, stackable strawberry plants or root bags.”

After planting, she fertilizes strawberries with earthworms to encourage a solid harvest, which happens sometime between mid-May to July, depending on the variety. Water your bed daily until you have got all the fruit for the season. Cover the bed with straw for the winter. In the spring, when the patch begins to grow again, Charles recommends cutting all dead brown fabrics.

The green spring favorite requires patience in the beginning. You will not harvest any for at least a year, probably two, if you plant ripe asparagus roots, known as crowns. (It takes three years before a harvest if you plant seeds.) “But then they are set and forget it,” says Charles. “All you have to do is weed them and eat them.”

For optimal growth, asparagus requires at least eight hours of sunlight a day. In general, asparagus can be sown directly into the soil; no raised bed is required unless you have extremely acidic soil. Simply dig a six-inch gutter and lay the crowns at the bottom. Do not overfill the bed. Leave 18 inches between each crown and one foot between each row. Water asparagus daily, but do not overwater as it can rot the roots and ruin your bed.

The vegetable that most people think is a fruit is not a sludge can in this region, which is often too hot. However, some gardeners experience serious success and harvest lots of stalks for pies, crumbs, jams and more. Consider rhubarb as one of the plants that requires a little luck to bloom. For the best chance of success, place a few roots in a six-foot square plot that gets a full day of sun. Over time, the plants will divide and fill the area. They require little maintenance; just keep them weeded and lightly fertilize them in the spring.

Rhubarb is a waiting game. “I would not touch it the first year. The second year you might be able to harvest a few stalks,” says Sheperd. “The third year you should be good at going with a full harvest from late spring to later in the summer.”

Unless you have a large yard with plenty of extra space, dwarf highbush blueberry plants are best because they grow about one to two feet tall and straight wide. Many are bred for container gardening, making them ideal for patios and porches. You need at least two plants so they can cross-pollinate, although several are recommended to guarantee a significant berry yield. Plan to harvest blueberries later in the summer, usually in July and August. To make sure you do not lose too many berries to the creatures of the neighborhood, cover the plants with nets. “But check the net every morning and evening to make sure a little songbird or snake was not snagged in it,” Jentz says.

Before winter, mulch the bushes. At some point during the cold months, prune them to remove dead and damaged branches. When spring comes, use a fertilizer designed for acid-loving plants.

Martell is an author based in Silver Spring, Md. His website is nevinmartell.com. Find him Twitter and Instagram: @nevinmartell.

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