Kale is one of the easiest and most versatile vegetables that you can grow. But, you might have wondered if kale is a perennial and whether it comes back every year.
The most common variety of kale, curly kale, is not a perennial. It’s a biennial. It completes its entire life cycle over two years. However, there are other varieties like Tree kale that are perennial and can be grown for several years.
Let’s take a look at this complex scenario in more detail.
Is Kale a Perennial?
Generally, curly kale is grown as an annual for its tender green leaves. However, this plant is actually a biennial. So what does this all mean? Here’s a quick explanation of these different plant life cycles.
|Plant Life Cycle||Explanation|
|Annual||The plant completes its entire cycle from seed to final seed production in one year.|
|Biennial||The plant takes two years to complete its life cycle. In the first year, it will put on lots of green growth (mainly leaves and stems). Then, in the second year, the plant completes its cycle by flowering and developing seeds.|
|Perennial||Perennial plants grow for two or more years and will generally complete one life cycle every year. Then, the following year these plants complete another cycle and so on, year after year.|
So, in the case of curly kale, the plant will produce its lovely tender green leaves in the summer, fall, and even throughout winter in some zones, in its first year of growth. Then, once the weather starts to warm up late in the following spring, the plant will start to bolt and produce flowers.
These flowers will then mature and eventually produce seeds for the next crop. You see, every plant’s primary aim is to reproduce, just like every other species on the planet.
Unfortunately, once your kale has started to bolt, you’ll find the leaves turn quite tough. But, you can still pick the leaves and use them in your cooking. They’ll just need to be cooked a little longer until they’re tender.
How To Grow Kale For More Than a Year
Although the most common form of kale (curly kale) is not a perennial but a biennial, you can allow it to grow for two years. This variety of kale does best in USDA zones 7 to 10, but it will survive in other zones. In zones that have temperatures of 25 to 28 degrees Fahrenheit (-4 to -2 degrees Celsius), the kale will go dormant and will grow again once the weather warms up.
The good news is that if you’re growing kale in zones 7 to 10, you’ll be able to harvest the leaves all winter long. But, make sure that you’re harvesting correctly to keep the plant growing.
When harvesting kale leaves, only take the ones from the very bottom of the plant and never harvest the leaves at the top. If you cut off the top leaves, the plant will stop growing.
So, in order to keep your kale growing, cut off the bottom leaves, stem and all, at the very base of the plant every time you want to harvest some kale. Continue harvesting these leaves as you move up the central stalk.
You should also remove any yellow leaves as this encourages the plant to continually produce more leaves during the cooler weather. Once the central stalk starts to thicken, you’ll know that the plant is going to bolt. You might be able to extend the growth stage a little by snipping off the flower buds as they start to grow.
Eventually, though, you’ll want to allow the plant to flower so that you can collect the seeds. You can then plant these early in the spring or fall so that you have more plants to harvest from.
How To Grow Tree Kale As a Perennial
If you want to grow kale as a perennial, you have to choose a variety that will grow happily for an extended period of time. Tuscan kale or Lacinato kale can be grown for an extended period, but there are others, such as Tree kale (also known as perpetual kale), that will grow as a perennial.
To keep your kale growing for the longest possible time, you must remember to harvest only the bottom leaves. Then, ensure that you provide the plant with plenty of organic compost and mulch heavily.
The mulching will help to keep the roots warmer, and this helps to “interrupt” the normal biennial cycle of this plant. This is because the bolting of the plant is stimulated by the cold.
Another way to make your kale plant last longer is to harvest the side shoots that will form along the trunk of the plant. Slice these shoots off the trunk very carefully so that you don’t damage the main plant.
These side shoots can now be planted in another spot or even into a pot. By doing this, you’re essentially extending the life of your kale by growing more.
How To Prepare Kale For Winter
There’s really not much you have to do to prepare kale for the winter as it tends to thrive over the colder months. As long as you’ve harvested only the lowest leaves, your kale will continue to grow.
However, if your winters do get very cold, it’s a good idea to mulch your plants heavily, as this helps to keep the roots warmer. If you do happen to have a prolonged freeze and your kale dies down, don’t worry. The plant will put on new growth as soon as the weather warms up.
Benefits And Drawbacks of Growing Kale As a Perennial
When you allow your kale to complete its natural cycle, you’ll be able to harvest the seeds. You can then plant these seeds for another successful crop. In this way, you’ll always have a continuous crop of nutritious kale growing in your garden.
Additionally, you can also eat the flower buds and even the kale flowers. In fact, the unopened buds taste very much like broccoli and can be added to salads or used in stir-fries.
The only drawback of allowing your kale to grow through its second year is that when the plant starts to bolt, the leaves will get much tougher. At this stage, they’re not really suitable for eating raw. However, you can use these leaves in your cooking as this will make them more palatable.
Will Kale Produce More Leaves If Grown As An Annual?
Growing kale as an annual does not automatically mean that it will grow more leaves. It just means that the leaves are more tender in their first season of growth.
To encourage your kale to thrive and grow as much as is possible, you have to supply it with plenty of nitrogen fertilizer. This is because nitrogen stimulates green plant growth. Also, the more you harvest, the lower leaves, the more new leaves your plant will produce.
Harvest Regularly Your Kale To Get Rid Of Pests
You’ll find the most annoying pests that attack your kale plants are the white cabbage moth or, rather, the caterpillars of this insect. Therefore, if you’re regularly harvesting your kale leaves, you might be inadvertently removing the eggs that these moths lay. Just make sure that you wash the leaves well before using them in your salads and cooking.