The Why and What of Perennial Vegetables

Written by Trent Rhode

There are more than just asparagus and rhubarb that keep coming back year after year with little effort, however. There are dozens of delectable perennial food plants that are, only now, gaining recognition in cool temperate climates.

But, before we go into some examples of these amazing plants, why would you even want to grow perennial vegetables?

To start with, once your perennials are established, assuming they are suited to your climate and site, they can be extremely tough. Not only are they usually more resistant to pests, due to energy reserves stored in roots, they are also more drought tolerant (deeper roots), and better at out-competing weeds. Their leaves are out suppressing the growth of weed seeds before some annuals are even in the ground.

Perennials also have great potential to extend the growing season. While seeds are still being started indoors, and seedlings are just being planted in the garden, perennials are already in full growth and ready to be eaten.

Perhaps the most significant benefit of perennial vegetables is their contribution to improved soil quality. Exposed soil quickly dries out and becomes susceptible to wind and rain erosion, while continually covered soil is more resistant to these forces. Well-mulched perennials need zero tilling once they are established (annual patches also need not be tilled if mulched heavily), preventing significant erosion that comes with the destruction of soil structure.

The continual growth and death cycle of a perennial’s deeper roots, and leaves, improves soil organic matter, soil structure and porosity. This cycle of growth and decay boosts soil life, including bacteria and fungi that feed on plant matter and help keep nutrients in the soil, and worms that break up soil, create humus and make nutrients more bio-available.

Finally, perennials make functional garden companions, providing beauty, ground cover, erosion control, beneficial insect and animal habitat and food, pest repellents, nitrogen fixation, and much more.

So, now that we have reviewed the benefits of perennial vegetables, we will take a look at a few examples:
 

Japanese Parsley or Mitsuba, Cryptotaenia japonica
Leaves can be eaten raw or cooked, and have a parsley-like flavour and usage. Seedlings and young leaves can be used in salads, but care must be taken when cooking, since flavour will be lost if overcooked (more than a couple of minutes). The stem can also be blanched and used as a celery substitute, and the seeds can be used as a seasoning.  

Wild Garlic, Allium ursinum
Like garlic, the bulbs of this plant are edible, with a pleasant mild taste. The leaves and flowers can also be eaten.

Bunching Onion, Allium fistulosum
This easy to grow perennial onion spreads and forms clumps of delectable bulbs, but the leaves are also edible. It is not uncommon to harvest them right into winter.

Common Day Lily, Hemerocallis fulva
The common day lily is a great perennial vegetable, and a tasty one. Both the flowers, and the lower stem just above the root where it is still white, are edible. But leaves should not be eaten in large quantities. The flowers are one of my favourite treats from the garden, with a pleasing sweet taste near the base where the nectar is found.

Common Sorrel, Rumex acetosa
This delicious, lemony, large-leaved green is not only a pleasant treat added to salads, but it is also a dynamic accumulator. It concentrates and draws nutrients to the soil surface with its deep roots.

Sea Kale, Crambe maritime
If you like kale, you will like sea kale. Although it is best cooked, this drought tolerant plant is every bit as nutritious as its less hardy relative. Unfortunately, sea kale plants can be difficult to find. I had to order from the United States, but for a perennial kale, it was definitely worth it.

Good King Henry, Chenopodium bonus-henricus
Although the raw leaves of this plant should only be eaten in small quantities, the cooked leaves can be eaten without cause for worry. The most notable thing about the Good King, however, is that the young shoots can be cooked and used like asparagus in the spring.

Solomon’s Seal, Polygonatum multiflorum
This is another plant whose young shoots can be cooked and used like asparagus in the spring, and it is often used as a decorate fixture in home gardens, especially in shady areas.

Jerusalem Artichoke, Helianthus tuberosus
The Jerusalem Artichoke is a root crop best cooked. Imagine all the ways to use potatoes and then substitute Jerusalem Artichoke.

These are just a few of your options when it comes to perennial vegetables, and we have not even touched on fruits and nuts. When it comes down to it, probably the most significant reason I grow perennial vegetables and other plants is simply because I can grow more with less work and fewer resources. Don’t get me wrong, I love tomatoes and eggplant as much as the next guy, but when it comes to gardening, I take a page from Mother Nature’s book and diversify.