Artichoke plants are perennial flowers and members of the sunflower, or Compositae, family. Still extremely popular in their native Mediterranean region, artichokes can be hard to find in the United States. California is the only state with a large commercial artichoke industry. There, peak growing season is from March to May, but you can have artichokes maturing in your home garden throughout the summer. Even in areas where artichoke plants are not hardy, gardeners can successfully grow them as annuals and still get plenty of delicious buds.
Much of the artichoke plant is edible, but the portion generally eaten is the immature flower bud. The unopened bud has overlapping rows of spine-tipped green bracts enclosing the actual flower parts. At the base of the bud is the tender, flavorful artichoke "heart" which is the part that is cooked and eaten.
- Leaves: The silvery-green leaves are long, arching and, although they look soft, they can be quite prickly. Stems are thick and fleshy.
- Flowers: The flower buds are what are sold in produce aisles. The bracts are tightly folded over the enclosed flower parts. If allowed to open on the plant, mature artichoke flowers open into large, dome- or muff-shaped, purple thistles that are surprisingly fragrant.
Artichoke, Globe Artichoke, French Artichoke, Green Artichoke
Artichoke plants are only reliably hardy in USDA Hardiness Zones 7-11. Artichokes favor coastal areas with mild winters (50-60 F) and cool (70-80 F), moist summers. Gardeners in colder zones can still grow artichokes either by choosing varieties that have been bred to produce buds in their first year, or by either tricking the plants into thinking they are in their second year, or over-wintering plants to grow as perennials.
Artichoke plants prefer full sun to partial shade. The plants can handle a little partial shade, especially in hot, dry areas, but they set buds best when grown in full sun.
Artichoke plants can get quite large and bushy, especially when grown as perennials for several years. Expect them to reach 5-6 feet (h) x 4-5 feet (w).
Days to Harvest
In ideal conditions, like coastal areas of the Mediterranean and California, established plants will produce buds periodically throughout the year. However, in most areas, buds begin forming in early summer. The center bud will mature first and can be harvested as soon as it has reached about 3 inches in diameter. Harvest while the bracts are still tightly folded and the bud feels firm. You can cut a 1 to 3-inch portion of the stem with the bud, to make it easier to work with.
After the center bud is cut, side shoots will begin producing smaller buds. Harvest when they are firm and reach about 1 to 3 inches in diameter. Small buds can be extremely tender and flavorful, requiring only a slight heating through before eating.
Once all the buds on the stem have been cut, the stem can be cut off at ground level. Frost free coastal areas may get a fall harvest. Perennial plants should continue to produce for up to five years.
- "Big Heart" - a thornless variety that can handle some heat
- "Green Globe" - the variety most often grown commercially in California, but it does not adapt as well to non-ideal growing conditions
- "Imperial Star" - widely adaptable, easy to grow from seed and bred to be grown as an annual. Imperial Star is the variety recommended for gardeners in Zones 6 and colder
- "Purple of Romagna" - tender Italian heirloom favored by chefs
- "Violetto" - an Italian heirloom favored for producing dozens of small side shoots
If artichokes sound like more work than you're up to, consider growing their cousin, the cardoon. Cardoons taste very similar to artichokes, but you eat the stem of the plant, rather than waiting for the buds to form.
Artichoke Growing Tips
Soil: Artichokes grow well in a neutral to slightly acidic soil pH of between 6.0 to 7.0. They need a well-draining, loamy soil with a good amount of organic matter. Good drainage is crucial to prevent the roots rotting during cool, damp winters, however, the soil must also be able to retain water long enough to allow the roots to take it in during hot summers. It is especially important when you are growing your artichokes as perennials to take the time to amend your soil before planting, to ensure they will grow well in future years. If your garden soil is poor, consider growing your artichokes in raised beds.
Growing Artichokes from Seed: Start seed indoors, at least 8 weeks before your last frost date. Harden them off before planting outside, but don't wait until all danger of frost has passed. Artichokes need to experience a slight chilling (not freezing) before they will set buds. This can be accomplished by putting your plants out in mid-spring and exposing them for a week to 10 days to temperatures of about 50 F or a little lower.
Artichokes do not often grow true to seed and you may get plants that vary greatly from your original plant if you try saving seed from your own plants. You will have better success with purchased seed that has been grown under controlled conditions.
Planting: Artichokes are often grown from crowns. It's quicker than growing from seed and you won't need the pre-chilling period. In zones 9-11, artichokes can be planted in either the spring or fall. Gardeners in cooler climates should do their planting in the spring.
Make sure you leave plenty of room for the plants to spread out as they grow. Perennial plants can branch out 5-6 feet. Artichokes that are grown as annuals, or where the tops will be killed back by frost, will not get as large and can be spaced a little closer.
Caring for Artichoke Plants
Keep the planting bed weed free. Adding a 3- to 4-inch layer of mulch will cut down on weeds and keep the roots cool and the soil moist.
Since these are large plants that flower and produce over a long season, they will benefit from periodic feeding. Apply a balanced fertilizer labeled for edible plants, every 2 to 3 weeks.
- Zones 8 and Higher: After the last harvest in fall, cut the plants to soil level and cover with 2-4 inches of an organic mulch, like straw.
- Zones 6-7: After the last harvest in the fall, cut the plants down to about 12-18 inches. Cover the plant with organic mulch, like straw, leaves, or even compost and then cover that with a large basket. Mound another layer of straw or leaves over the basket and cover everything with a waterproof tarp.
- Zone 5 and Cooler: You can try the method given above, for Zones 6-7 or you can pot up your plants, move them to a dark spot that stays cool, but above freezing, and water occasionally throughout the winter. Move pots outdoors, after all danger of frost, and either replant in soil or continue to grow in containers.
Whatever your zone or method, remove all the covering in spring, as soon as the soil has thawed and no hard frosts are expected.
Artichoke plants should produce for about 3-5 years. At that time, you should notice side shoots at the base of the plant. You can lift, divide and replant the new shoots.
Using Artichokes as Ornamental Plants
Artichokes are often described as architectural plants and one look at a tall, branching specimen will tell you why. Since few animals attack artichokes, don't be afraid to plant them in your ornamental borders, as edible landscaping. You can still harvest them at will, but the stately plants and textural leaves will add visual interest throughout the season.
Artichoke Pests and Problems
Few pests attack artichokes. Slugs can be a problem during damp weather, especially with younger, tender leaves. Aphids can also become a nuisance but can be hosed off, before they take over. Giving the plants enough space for air to flow freely will help cut back on aphid problems.
Botrytis, or gray mold, can affect leaves and flower bracts. It is most pervasive on damaged leaves, which will turn brown and then grayish. Remove affected leaves as soon as the disease is noticed. For severe infections, use a fungicide labeled for edible plants, such as neem.