Is Kale an Annual or Perennial?

Is Kale an Annual or Perennial?

There are plenty of reasons why you might want to know whether kale, the star of many a spring or fall veggie garden, is an annual or perennial.

Armed with this knowledge, you will be able to answer some of the other questions you may have about growing this cruciferous crop in your garden.

Some of those questions may go along these lines. Do you have to replant it every year? Can you harvest and save seeds from it the first year?

If it looks good at the end of summer, should you try to overwinter it or should you pull it up and put it on the compost pile?

Excellent questions, indeed, and you will soon discover the answers. Before we get started, here’s a quick overview of what I’ll cover:

Is it an Annual or a Perennial?

For gardening purposes, it’s important to know that annuals must be replanted every year, while longer-lived perennials will keep growing year after year.

You can learn more about the differences between annuals and perennials in our handy article.

A close up of a large curly kale plant growing in the garden with frilly dark green leaves and light green stems and veins on a soft focus background.

So which group does kale fall into?

The short answer – it depends what type you’re talking about! Some kale varieties are perennial, and I’ll get to them later, but most varieties are neither an annual nor a perennial.

A close up of a purple curly kale plant growing in the garden with a fence and other vegetation in soft focus in the background.

Unlike annuals that are destined to live and die in just one growing season, or perennials that live on year after year, some plants have a different fate.

Called “biennials,” these plants complete their reproduction (and entire life cycle) over a two-year period.

A close up of a green kale plant that has started to bolt and produce flowers before going to seed.

Kale is one such plant – and it finds itself in good company! Carrots, parsley, leeks, and hollyhocks are also biennial plants.

A Two-Year Cycle

As biennials, in their first season in your garden, kale plants will put all their energy into leaf production, growing bushy, and lush under the right conditions.

A close up of a curly kale leaf with the rest of the plant in soft focus in the background.

To learn more about how to grow kale, see our growing guide here.

In USDA Hardiness Zones 7-10, biennial kale will continue to produce edible leaves throughout the winter.

While in colder Zones, these plants will go dormant during the winter – which means their leaves may die back, but their root systems will remain alive.

At this point, some gardeners may assume that the plant is dead.

How cold hardy are these biennial plants exactly?

It varies according to the cultivar – with the hardiest kale varieties being able to survive sub-zero temperatures, and most others continue to thrive through moderate freezes (25-28°F).

A close up of a purple curly kale plant growing in the garden covered in a light dusting of frost in gentle sunshine on a soft focus background.

After the first winter, your biennial kale plants will begin to put more of their energy into reproduction, and less energy into leaf growth.

Yes, this is the birds and the bees part – which is the whole reason why plants produce flowers in the first place.

The plant will bolt and flower then eventually set seed before dying back.

A vertical picture of a kale plant that has bolted and started flowering with a house in the background in soft focus.

While the biennial is focused on reproduction in the second year, its edible leaves will not be as tender, so may be better suited for use in cooking than eating raw.

Shortly after your plants start flowering, you’ll begin to see long, slender seed pods developing.

A hand from the bottom of the frame touches a seed pod on a kale plant with yellow flowers surrounding it on a soft focus green background.

When these pods dry out, you can harvest them to save the seeds for sowing a new crop next season.

Perennial Varieties

While most kale varieties a gardener is likely to encounter will be biennials, there are some types that are actually perennials. Here are a few of them:

Daubenton ( var. )

Named after a French naturalist, ‘Daubenton’ is a short-lived perennial variety that doesn’t go to seed – instead it is propagated through cuttings. It is a cultivated variety, not found growing wild.

Living for 5-6 years, ‘Daubenton’ is perennial in USDA Hardiness Zones 6-9, and hardy down to 10°F.

When the plant starts to reach the end of its life a root cutting can be taken from it to start a new plant, keeping the variety growing in your garden for as long as you keep propagating it.

While it is very difficult to source root cuttings of ‘Daubenton,’ there is a variegated cultivar called ‘Kosmic’ that is available via Amazon.

‘Kosmic’

Sometimes known as perpetual kale, the leaves of this green are mild and nutty tasting, less bitter than its biennial relatives.

You’ll find root cuttings for this variegated cultivar of var. called ‘Kosmic’ available via Amazon.

Walking Stick ( var. )

Also known as Jersey cabbage, tree cabbage, and by a plethora of other local names, ‘Walking Stick’ kale is native to the Channel Islands, an archipelago in the waters between France and England.

This cruciferous plant gets its vivid common name from its long stalks, which were traditionally dried and purposed into – you guessed it – walking sticks.

‘Walking Stick’

Hardy down to 10°F or lower and perennial in USDA Zones 6-9, ‘Walking Stick’ prefers neutral or alkaline soils.

The proper harvesting of the leaves will encourage this plant to grow long stalks, which easily grow to 6-10 feet tall at maturity as a backyard garden plant but can rise to a towering 20 feet tall in certain conditions.

Traditionally the leaves of this plant were used as animal fodder, but seed saving enthusiasts have brought it back as a culinary oddity.

To prepare, remove the tough mid-vein and cook the leaves as you would other kale for a sweet, nutty green.

You’ll find packs of 45 ‘Walking Stick’ seeds for sale at Hirt’s Gardens via Amazon.

Sea Kale ()

Now for something a little bit different.

Sea kale is a more distant relative of kale, but still a member of the Brassicaceae family, and is native to Northern European coastlines where it grows wild.

It is hardy in Zones 6-9 and will grow well in coastal areas of the Pacific Northwest, where the cool summers are similar to those of its native habitat.

A close up of a flowering sea kale plant, Crambe maritima growing in the wild set on a soft focus background.

Of great interest to perennial vegetable gardeners, this plant grows well in sandy soil. It can be grown from seed, though the germination rate is low, so buy more than you think you need.

Sea Kale,

If the young shoots and leaves from this plant are blanched while they are growing, it gives them a pleasant nutty flavor when cooked.

You can find packs of 50 seeds from Wicked Vegetables via Amazon.

A Tale of Two Kales

Along with understanding kale’s status in the annual vs. perennial debate, by now you should even be able to answer those other questions I mentioned at the beginning of the article.

While most kale varieties you come across will be biennials, there are some perennial cultivars that would make exotic additions to your perennial beds.

A close up of Tuscan kale leaves on the plant growing in the garden with droplets of water on the dark green leaves in light sunshine on a soft focus background.

Now that you know how to think about the life cycle of this veggie, will you be sticking to biennial kale – or are you considering trying out one of the perennial varieties? Let us know in the comments.

The article “Is Kale an Annual or a Perennial?” was first posted here

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