Annual vegetables are familiar favourites in many gardens. Many gardeners are used to growing annuals from seed each year to feed themselves and their families. But fewer gardeners are aware of the potential of perennial vegetables. While these may not be as familiar as their annual cousins, they can be a great choice. Unlike annuals, they will grow in your garden not just for one season, but will return year after year.
What Are Perennial Vegetables?
If you are new to gardening, you may not be familiar with the word ‘perennial’. Perennial is just a term used to describe plants that live in your garden not just for one year, but over a number of years. It is likely that you are already familiar with a range of perennial plants that provide food, such as:
You may be less familiar, however, with vegetables that will grow in your garden year after year.
Most of the vegetables that are traditionally grown in gardens are annuals (or biennials – with a two year growing habit). Almost all are sown in the spring or summer and harvested later in the year. There are only a couple of common exceptions: asparagus, and rhubarb. These two are the most common perennial vegetables that are grown. You may also have heard of globe artichokes – another perennial vegetable option.
However, you may be surprised to learn that there are a wide range of other perennial vegetables that you could grow.
Rhubarb is one of the best known perennial vegetables.
Which Perennial Vegetables Could I Consider?
There are a range of interesting and unusual types and varietals to consider, these include:
Leafy Green Perennial Vegetables:
Rather than growing annual brassicas and other common annual leafy greens, you could consider:
Nine Star Perennial Broccoli
This member of the cabbage family produces heads that resemble mini cauliflowers but taste more like broccoli. After the main head has been harvested, it will produce around nine smaller but no less tasty heads that look and taste like any annual sprouting broccoli. Prevent it from setting seed and it will keep producing its crop every spring for around five years, sometimes longer.
Much sought after as a perennial vegetable, Daubenton’s Kale is one of the best and most resilient perennial greens that you will find. Just like regular kale, this plant is extremely good for you and can be used in a range of recipes – but this kale is truly perennial and will continue to produce good, leafy growth for years.
Another cabbage-family option is ‘Everlasting cabbage’, which you can find in green and variegated varieties. When given good quantities of nutrition and water, this plant will be an abundant source of leafy greens throughout much of the year.
Sea Kale (Crambe maritima)
Sea kale grows close to the sea, but could also be grown in many gardens.
A less well known member of the Brassica family, perhaps, this plant may be familiar to anyone who has foraged along the seashores of Europe, where this plant can often be found. The plant has leaves much like any other Brassica but as it likes dry and free-draining conditions, could be an excellent choice for areas where rainwater can be scarce in summer.
Good King Henry
Good King Henry is not very well known today, but was, for hundreds of years, a commonplace vegetable in cottage gardens. The leaves of Good King Henry can be used in much the same way as spinach, while the young shoots are a substitute for asparagus. Useful and versatile, Good King Henry is ideal for edible greens and for ‘poor man’s asparagus’. It is hardy and reliable and easy to care for, making it the perfect addition to a perennial planting plan.
Instead of (or as well as) growing annual onions in your polytunnel from seed or from sets, you could also consider growing some perennial onion alternatives. These include:
Bunching Onions (Allium fistulosum)
Bunching or winter onions can be a very useful crop.
These hardy onions are harvested and used as spring onions or green onions. But the difference is that you can enjoy these ‘spring’ onions throughout the winter. These take up little space and once established, will endure for years in a perennial vegetable bed.
Egyptian ‘Walking’ Onions (A. cepa proliferum)
These unusual onions ‘walk’ along. They develop bulblets on the top of their tall stems in the early summer, which then bend down and root where they touch the soil. The leaves can be used like spring onions and the bulblets can be cooked whole in soups and stews.
Potato Onions (A. cepa aggregatum)
Like shallots, potato onions form several bulbs from each one planted, but these are stronger than shallots and are perfect for where a stronger onion flavour is needed. Potato onions are also even more productive than shallots and you can make re-plantings in either the autumn or in the spring.
Babington’s Leek (A. ampeloprasum var. babingtonii)
Babington’s Leek, which tastes almost identical to regular, annual leeks, has a distinct advantage in that it is a true perennial, tough and requiring little maintenance. Simply leave the plant to establish itself for a year and then you can harvest by cutting off the small leeks above soil level. The baby leeks will then regrow from the bulb.
Elephant Garlic (Allium ampeloprasum)
Elephant garlic is an interesting alternative to regular garlic.
Elephant garlic, Allium ampeloprasum, is a relative of onions, leeks and garlic. It has most in common with the last two of these. Like the leek, it has a tall stalk and flat leaves. It is garlic-like in flavour and, like garlic, forms a bulb that is made up of cloves. However, the bulb is much larger than that of regular garlic, and it is a perennial crop.
In addition to considering the above, it is also worthwhile considering the potential of other perennial edible plants that are commonly considered to be weeds. Some ‘weeds’ can also be useful and versatile perennial vegetables. For example, the common stinging nettle, fat hen, chickweed, dandelions and more.
You may also wish to consider perennial plants that are usually considered to be ornamental, but which have great potential as edible plants. One great example is the hosta. All hostas are edible, and taste great. Most people who grow them, however, are unaware that they can also be used as a vegetable. The same is true of a number of other perennial flowering or ornamental plants.
The Benefits of Perennial Vegetables
There are a wide range of reasons why it is a wonderful idea to grow perennial vegetables in your garden. First of all, there are the benefits to the gardener:
- Far less work involved in sowing or planting your crop, since it needs to be done only once, not every single year.
- Less digging/ soil preparation. Perennial vegetables, once planted, will frequently require little ongoing work. You won’t have to prepare and tend a growing area anew each year.
- Reduced requirements in terms of ongoing maintenance. Perennial vegetables are usually grown in self-maintaining polycultures (more on which below), which can pretty much take care of themselves. Annual crops usually require a lot more ongoing work throughout the season.
There are also benefits to the natural world:
- Growing perennial vegetables protects the soil, since you will not be disrupting it to sow, grow and harvest your crops each year.
- Perennial vegetables can be a boon to wildlife, creating a thriving, biodiverse ecosystem that can endure year after year.
- As part of a polyculture, perennial vegetables can aid surrounding plants. Plants remaining in the ground year after year will help one another in a wide range of different ways.
These are just some of the reasons to consider creating a perennial vegetable growing area in your garden.
How To Grow Perennial Vegetables
Perennial vegetables can be grown from seed, or planted out as bare root or pot grown plants in the spring or fall. How and where you choose to grow them exactly will depend on where you live and the conditions to be found there.
However, while the requirements of the individual plants, and how they react to their environment will differ, there are certain practices to follow for all perennial vegetables. Mostly, these practices centre around the creation of polycultures.
Creating Polycultures for Perennial Vegetables
One of the key practices in organic gardening involves increasing biodiversity as much as possible. For one thing, the more diversity you can include in the garden system, the more you avoid putting all your eggs in one basket. For another thing, the higher the diversity in a system, the more beneficial interactions between the plants and other elements there are. The more beneficial interactions there are, the more resilient and stable a system will be.
It is a good idea to create polyculture growing areas for your perennial vegetables. These areas might also include:
- perennial fruits
- perennial herbs
- perennial flowering plants to provide other benefits such as attraction of pollinators or predatory insects, or other beneficial wildlife.
Perennial vegetables can work well on the fringes of a forest garden. They can also work well in mixed perennial borders or beds, which can be beautiful as well as useful.
You can make new growing areas for your perennial vegetables and their companion plants by using permaculture techniques such as sheet-mulching/ lasagna bed creation, or hugelkultur, for example. Be sure to think about how you can use natural resources around you to create fertile and healthy growing areas for your perennial plants.
Maintaining Perennial Polycultures
Whichever perennial vegetables and other perennial plants you choose to include in your perennial polycultures, it is important to think about how the fertility of those areas will be maintained over time. In a successful polyculture, the plants themselves, and other garden helpers – wildlife above and below the soil – will cater for a lot of the needs of the edible plants you wish to grow. This reduces the amount of work for the gardener – though of course there will still be some work that you have to do.
A gardener will tend a perennial vegetable polyculture by:
- Watering well and consistently, especially during periods of dry weather, and especially until the polyculture becomes established.
- Mulching with organic matter to maintain soil fertility. (Sometimes this may simply be a case of chopping and dropping certain plants around the perennial vegetables and other perennial plants.)
- Harvesting leafy green perennial vegetables little and often during the growing season, and lifting and dividing perennial onions as and when required.
But human agency is not the only thing acting on the garden and maintaining it over time. You will likely also have:
- Dynamic accumulator plants drawing nutrients from deep below the soil, or fixing nitrogen from the air with the help of bacteria on their root nodules.
- Plants attracting beneficial wildlife like pollinators and predatory insects which help keep the garden in balance and keep number of pest species down.
- Bacteria, fungi and other creatures like earthworms working below the soil to maintain the vital soil web, and transport water and nutrients to your plants.
Using Perennial Vegetables
Perennial vegetables differ from annual vegetables in that they will remain in the ground and come back year after year. But one of the great things about them is that they can often be used in much the same way as equivalent annual crops.
The leafy green perennial plants mentioned above can be the equivalent of common annual crops like broccoli, cabbage, and other brassicas, or other leafy greens like spinach or chard. They can be cooked in much the same way as these plants and used as replacements or alternatives to them in a range of recipes.
Likewise, the perennial onions described above can be used as alternatives to spring onions or scallions, white onions or leeks. These too need not restrict your diet and can be used in a huge range of different ways in the kitchen.
So if you want to live more sustainably, and go greener in your garden, creating perennial polycultures and growing some perennial vegetables could be a great way to go.