Why Grow Perennial Vegetables

Perennial vegetables are edible plants that live for at least three years, sometimes decades. Edible parts include leaves, stems, shoots, buds, and roots. Common examples grown in cold climates include asparagus and rhubarb, but there are hundreds more. Perennial vegetables have many benefits over annual or biennial vegetables commonly grown in gardens: they are generally less work, more nutritious, and more resilient. Let's dig into some of their advantages below. 

The Homesteader's Kaleidoscopic Perennial Kale Grex can be harvested in winter, pictured here in late February.

Less Work

Plant them once and harvest for years to come! After their initial seeding or transplanting, perennial vegetables come back reliably year after year. No more fiddling with seed trays and grow lights in late winter. After shifting my garden to mostly perennials, the spring seeding rush has reduced a lot and I spend more time harvesting instead of seeding in spring!

Because they live for many years, perennial vegetables don't require tilling every spring either. This frees up a lot of time otherwise spent preparing beds for planting. Usually all they require is some amending with compost, and if desired, some pruning and fall tidying.

More Nutritious

A 2022 study by Eric Toensmeier et al. tested nutrient levels of perennial vegetables compared to their annual counterparts. In most cases, perennial vegetable knocked annuals out of the park!

There is a great chart in the study that ranks perennial vegetables from high to extremely high for nine nutrients that people are commonly deficient in due to our modern diets. I adapted the chart below so it's a bit easier to read. 

Since perennials live for many years and have large root systems, they are likely able to scavenge for more nutrients in the soil, resulting in more nutritious edible parts. Since the nutrients in crops have declined significantly since the 1950s, perennial vegetables provide important nutrition. 

More Resilient

Perennial vegetables often have deep root systems, which seems to make them more resilient to stressors such as drought and pests. Deep roots help the plants reach water during hot and dry weather, helping to reduce the need for watering. Perennial vegetables also seem to bounce back more readily to pests such as deer or aphids, possibly because the large root systems provide an energy reserve that plants can draw on to regrow. Perennial vegetables do still get pests such as aphids and cabbage moths, but they seem to withstand them quite well and recover easily in fall or the following spring. I don't sweat the pests like I used to!

Can Grow on "Marginal" Land 

Perennial vegetables can grow in areas that may be considered "marginal" for conventional agriculture such as steep slopes, wet areas, ponds, dry or salty soils, and shade. There's a perennial vegetable for every microclimate in your yard! One classic perennial vegetable that can grow in deep shade is Caucasian Spinach. It's a long-lived perennial spinach alternative that grows vines about 10 feet long that die back in winter. The shoots emerge in late winter and can be eaten like mini asparagus, and the leaves taste very similar to spinach. They can be trained to grow up fruit trees or on the shady side of a fence, saving space in small yards. 

Caucasian Spinach Seeds - Climbing Spinach - Hablitzia tamnoides - Aka Habby / Climbing Spinach Vine

Low Maintenance

Perennial vegetables require little maintenance. I like to apply compost annually to all my perennial beds for nutrients and also as a mulch. If desired, additional mulches such as straw, leaves, or woodchips can be applied instead of, or in addition to compost. Perennial vegetables often require less feeding than annual vegetables because their large root systems can better scavenge nutrients. 

Once established, perennials such as trees, shrubs, and perennial kale may require pruning to keep them a manageable size. Herbaceous perennials often benefit from thinning or dividing every few years to maintain their vigour as well. Weeding is especially important for smaller perennials that are more easily out-completed by weeds. I find that between mulching and the lack of tilling (that brings weed seeds to the soil surface), there isn't much weeding required. 

Promote Soil Health

Since perennial vegetables don't require annual tilling, so soil structure and soil biology are better preserved. Good soil structure helps retain humus, prevents soil and nutrients from eroding away, and better regulates moisture, helping plants grow better. 

Additionally, symbiotic mycorrhizal fungi are able to attach to plant roots and help feed the plant in exchange for root sugars. Since perennials have living roots in the soil year round, they support soil life year round. 

Sequester Carbon

Conventional agriculture is a major contributor to greenhouse gas emissions. Tilling the soil exposes organic matter to the air, which accelerates microbes breaking it down and releasing carbon dioxide into the atmosphere. Going no-till reduces emissions and can actually help store carbon in the soil, in part because mycorrhizal fungi remain undisturbed, which are essential for carbon sequestration.

A Plant for Every Niche

Have you heard of the seven layers of plants in forest gardening? It's a central concept in permaculture, referring to different niches that plants can occupy in a forest for maximum ecological and edible productivity. Although examples of perennial vegetables aren't usually given when explaining this concept, they can be used in every layer! The layers are:

  1. Canopy: tall trees. Usually fruit and nut trees are used, but trees with edible leaves and/or flowers such as mulberry, linden, bigleaf maple, or black locust could be used here. Keep in mind that ladders may need to be use for harvesting since the edible parts don't fall to the ground like fruit or nuts do.
  2. Lower canopy: Dwarf fruit and nut trees are usually used, but consider smaller trees such as toona, or larger trees that are coppiced regularly like linden, or mulberry.
  3. Shrubs: Fruit bushes such as currants and berries are usually used, but shrubs with edible leaves such as saltbush, udo, or goji could be used. Also consider larger vegetables like perennial kale.
  4. Herbs: Smaller culinary, medicinal, and support plants- lots of perennial vegetables to choose from here!
  5. Ground covers: Living mulch plants like strawberries are often listed, but low-growing perennial vegetables such as sedums, good king henry, or minutina could be used here.
  6. Rhizosphere: There are so many perennial root crops to choose from! Try groundnut, Chinese yam, crosnes, skirret, oca, chuffa, potato onions, camas, black salsify, and more.
  7. Vines: Caucasian spinach, maypop, grapes (for leaves), mashua, hops, groundnut and Chinese yam are a few examples.

You'll probably want to integrate fruits and nuts into your forest garden, but this list shows that there are lots of perennial vegetables to integrate if you're so inclined.

Forest Garden Diagram by Diagram by Graham Burnet. Image via Wikimedia Commons licensed under GNU Free Documentation License 

Long-lived

Some perennial vegetables can live for decades. Asparagus can live for over 40 years, and Caucasian Spinach can live for over 50 years. Imagine planting spinach once and then harvesting it for the rest of your life!

Extend the Harvest Season

Harvests of perennial vegetables are generally more evenly distributed throughout the year. They really shine during the "hunger gap" in late spring when overwintered vegetables have been harvested, and spring-planted vegetables are not yet mature. Some perennials can be harvested during the winter as well such as Korean celery, Caucasian spinach, perennial kale, and leeks, and hardy root crops such as groundnut and Chinese yam can be dug as long as the ground isn't frozen. 

Korean Celery is perfectly fine to harvest even when frozen. Pictured here in early February.

Support Pollinators & Other Beneficial Insects

Since perennial vegetables are allowed to remain in the ground year-round, they are able to flower, which feeds pollinators and other beneficial insects such as wasps that parasitize aphids. Many plants have hollow stems that solitary bees can nest in. Additionally, plants will drop their leaves in fall, providing a mulch layer for insects to hibernate under. And no tilling means ground nesting bees aren't disturbed (most solitary bees nest in the ground!). There's also something wonderful about witnessing a plant complete its full lifecycle!

Many Native Plant Options

We are lucky here on Turtle Island (North America) to have many native perennial vegetable options. Groundnut, American hog-peanut, fireweed, wapato, cattail, lady fern, bugleweed, milkweed, sochan, cow parsnip, stiff cowbane, bigleaf maple, camas, biscuitroot, stinging nettle, silverweed..... the list goes on and on! Many of these species have been cultivated and selected by Indigenous peoples for millennia, making them into the incredible vegetables they are today. 

Beautiful

Last but not least, perennial vegetables are beautiful to grow. They're just as at home in the flower garden as they are the vegetable garden. Many have showy foliage and flowers. They've even been coined "Edimentals" by Stephen Barstow, short for edible ornamentals. Stephen runs a great blog about perennial vegetables, which I encourage everyone to check out. 

Shop Perennial Vegetables

Find all our perennial vegetables here. All our seeds are grown ecologically without synthetic pesticides or fertilizers. We grow 95% of our seeds, and partner with a few farmers we know personally for the other 5%. All seeds are grown in Canada, but we ship almost worldwide!

Further Reading

Books

Books about perennial vegetables that I highly recommend:

  • How to Grow perennial Vegetables, by Martin Crawford
  • Perennial Vegetables, by Eric Toensmeier
  • Around the World in 80 Plants, by Stephen Barstow

Blogs

Some of my favourite blogs about perennial vegetables: