Artichokes, Cynara cardunculus var. scolymus, grow as perennials in Zones 7 to 10 and can be cultivated as annuals in Zones 6 and below.
But with a little bit of extra work, you can winterize your artichokes and enjoy them year after year in cold regions.
The trick to cold weather survival is to pick a hardy cultivar and then figure out which of the three methods you want to use to help it survive the winter.
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In our guide to growing artichokes, we cover how to cultivate these unusual vegetables in your garden.
When winter rolls around, you’ve got three main options for keeping your artichokes alive, and that’s what we’ll discuss in this article.
How to Winterize Artichokes
Artichokes are Mediterranean vegetables that thrive with daytime temperatures around 70°F and overnight about 10 to 15 degrees lower.
To produce the edible “heads” they require a period of vernalization, aka “chill hours” which varies depending on the cultivar.
Cultivars with higher chill hours are suitable for growing in cooler climates while those that have low requirements are ideal for warmer regions.
In general, mature artichoke plants will suffer damage at temperatures under 25°F.
Regardless of which winterizing method you choose, don’t feed your plants at all after harvest. You don’t want to encourage new growth when we’re trying to put them to bed for the winter.
You should also avoid overwintering any plant that shows extensive damage from pests or diseases, so give your artichokes a thorough once-over and pitch any that appear infested or infected.
The first step in growing artichokes in cold climates is to choose a cultivar that can tolerate the less-than-ideal weather. Let’s discuss those first.
Best Options for Cold Climates
Set yourself up for success by choosing an artichoke cultivar that tolerates cold weather and has a short growing season.
If you grow cultivars that prefer hot climates, you run a higher risk that the plant will be killed during the winter.
Green Globe
’Green Globe’ is a classic heirloom choice that has been around for decades and thrives happily even in northern areas.
It’s ready in just 75 days from planting with five or more buds on each specimen, even in the first year.
If ‘Green Globe’ sounds like the right option for you, visit Botanical Interests to pick up a packet of seeds.
Imperial Star
‘Imperial Star’ grows to about four feet tall and can produce a harvest in the first year. Each artichoke produces up to eight buds that are four inches in diameter.
If you’d like to snag 25 seeds or a three plant bundle, visit Burpee.
Wonder
‘Wonder’ is an excellent hybrid with five-inch buds that mature in just 90 days, so it has plenty of time to mature even in short growing seasons.
Snag ten, 100, 250, 500, one million, or five million seeds at High Mowing Seeds.
’Colorado Star,’ ‘Imperial Star Purple,’ and other purple cultivars tend to be tolerant of cold weather, as well.
Overwintering in Place
In USDA Hardiness Zones 7 and up, you can leave your artichokes in place. Zone 6 is a bit of a gray area and plants will require protection. Some may be fine but you may risk losing them.
If your region drops to 25°F or below, to help them make it through the winter unscathed, add up to a foot of mulch on top of the soil.
Cut back the stem or stems to a few inches above the ground. Then, heap eight to 12 inches of oak leaves or straw over the area.
In colder regions, you might even want to put two feet of mulch to be safe.
This can be done anytime after first frost.
If you live in a region that is extremely wet in the winter, like the Pacific Northwest, it’s a good idea to cover the plant with something that will keep the water out, as wet, soggy mulch can cause rot.
I use upturned buckets or laundry baskets over my plants, but you could also lay garbage bags or a tarp over the area and pin them down.
Remove the cover about a month before the last predicted frost date.
In the spring, after the last predicted frost date, or when you start to see shoots emerging, remove the mulch.
Bare Roots in Storage
Artichokes growing in cooler areas should be dug up and stored during the winter.
If you live in Zones 6b and lower, it’s probably wise to dig up and store your plants in an unheated garage or basement instead of risking them in the ground.
You want an area where the temperatures stay between about 35 and 50°F but never freeze.
To do this, cut back the foliage to a couple of inches above the ground, dig the roots up and gently brush away the soil.
Try to keep as much of the root ball intact as you can. Then bury the roots in a pot filled with sand or peat and moisten it thoroughly.
Keep the medium moist but not wet throughout the winter. Don’t expose the plants to direct sunlight as this could encourage growth at a time when we want them to remain dormant.
When the last predicted frost date has come and gone, you can replant the roots in the garden. Gently remove the roots from the medium and examine them. Any that are mushy or black should be discarded.
Dig a hole about the size of the roots and plant them with the stem side just buried under the ground. Water well and watch for shoots to develop and emerge.
Plants in Containers
If you don’t want to dig up the roots, you can leave them in soil and move them to containers instead.
Of course, if you’re already growing your artichokes in containers, this is simple, as you just need to move the pots into a protected area for the winter months.
To relocate in-ground plants, find a pot that is large enough that it can hold the entire root ball. If you need to add a bit more soil to the pot, use a well-draining commercial potting mix.
If the pot is large, place it on wheels or put it in place before filling it with soil.
You want a spot that stays between 35 and 50°F all winter, which means an unheated garage or basement. They don’t need to be in sunlight, but a little direct light won’t hurt the artichoke plants.
Prune the main stem back to about six inches above the ground. Gently dig up the plant and brush away some of the soil from the root ball.
Place the roots in the pot and fill in around them with potting soil. Water them every six weeks or so.
When the last predicted frost date comes and goes, begin moving the pot back outside gradually – a bit like you would if you were hardening off seedlings.
Bring it out for an hour on the first day and then take it back in. Add another hour the next day, and a third hour on the third day, and so on for a week.
After a week, you can plant the artichokes in the ground or keep them in the containers.
Hunker Down and Chill
Don’t you love it when you find out that a plant you assumed would never survive in your climate can be a viable option?
Artichokes don’t have to be the domain of warm-weather growers, and with a bit of winter protection, you don’t need to treat them as annuals.
Winterizing doesn’t take much effort or space. Which method do you plan to use? Which cultivar are you growing? Share your setup with us in the comments section below.
And for more information about winterizing other garden vegetables, check out these guides next:
