Heirloom

Porto Spineless

Cynara cardunculus

Wikimedia Commons

The midrib and leaf stalks of cardoon have a similar flavor to artichoke when boiled (not for eating raw). Both portions are commonly used as a side vegetable, addition to stuffing, or in soups and stews. Cardoon must be blanched before it can be eaten. To blanch, tie the stalks up firmly and wrap with black plastic or black-and-white newspaper. If left unharvested, the 3-4' tall plants will produce large purple thistle-like flowers. The sharply lobed and serrated silver-green leaves are a unique addition to flower arrangements. Significantly reduced spines. Perennial in Zones 6-10.

Harvest

100d

Days to harvest

📅

Sun

Full sun

☀️

Zones

7–10

USDA hardiness

🗺️

Height

3-6 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Harvest

Start Indoors

Transplant

Harvest

Showing dates for Porto Spineless in USDA Zone 7

All Zone 7 herb →

Zone Map

Click a state to update dates

Porto Spineless · Zones 7–10

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing24-36 inches

SoilWell-drained loam, moderately fertile

WaterRegular, keep soil consistently moist during growing season

SeasonTender Perennial

FlavorSimilar to artichoke with a mild, slightly nutty taste when blanched and cooked.

ColorSilver-green with pale blanched stalks

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	April – May	June – July	—	July – October
Zone 4	March – April	June – July	—	July – October
Zone 5	March – April	May – June	—	June – October
Zone 6	March – April	May – June	—	June – November
Zone 7	February – March	April – June	—	June – November
Zone 8	February – March	April – May	—	May – December
Zone 9	January – February	March – April	—	April – December
Zone 10	January – January	February – April	—	April – December

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: Clay, High Organic Matter, Sand, Shallow Rocky. Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist, Occasionally Dry. Height: 3 ft. 0 in. - 6 ft. 0 in.. Spread: 2 ft. 0 in. - 3 ft. 0 in.. Spacing: 3 feet-6 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Division, Root Cutting, Seed. Regions: Coastal, Piedmont.

Harvesting

White to brown cylindrical fruits with numerous bristles are attached at the base.

Color: Brown/Copper, White. Length: < 1 inch. Width: < 1 inch.

Harvest time: Fall

Edibility: Leaf stalks are blanched, harvested, and cooked as a vegetable. Roots may also be cooked and eaten.

Storage & Preservation

Porto Spineless cardoons are best stored in the crisper drawer at 32–40°F with 90–95% humidity, wrapped loosely in damp cloth or perforated plastic bags to prevent moisture loss while allowing air circulation. Fresh stalks maintain quality for 7–10 days under these conditions. For longer preservation, blanch stalks for 3–4 minutes, cool immediately, and freeze in airtight containers for up to eight months. Drying is also effective: slice stalks lengthwise, dry at 95–105°F until brittle, then store in airtight jars away from light. Fermentation works well for a tangy condiment—pack blanched stalks in brine with garlic and herbs for three to four weeks. A particular advantage of Porto Spineless is its tender, thornless ribs require minimal peeling before storage or preservation, reducing prep time compared to spined varieties and lowering the risk of product damage during handling.

History & Origin

Origin: Europe, Africa

Advantages

+Attracts: Bees, Butterflies, Pollinators
+Edible: Leaf stalks are blanched, harvested, and cooked as a vegetable. Roots may also be cooked and eaten.
+Fast-growing
+Low maintenance

Companion Plants

Tomatoes and Porto Spineless have similar long-season timelines, and in our zone 7 Georgia gardens cardoon's deep taproot pulls moisture from well below where tomato roots concentrate, so they're not fighting each other for water. Marigolds at the bed edge add nematode suppression, worth doing in heavy clay soils where root-knot nematodes (Meloidogyne spp.) build up fast. Sage, thyme, and lavender attract parasitic wasps and tolerate the occasional dry stretch cardoon shrugs off anyway. Cucumbers, pumpkins, and lettuce are all aggressive surface feeders that spread wide fast — any of them planted within 2 feet will crowd out a cardoon seedling before it hits its stride at around 60 days post-transplant.

Plant Together

Tomatoes

Rosemary repels tomato hornworms and other pests that damage tomatoes

Cabbage

Rosemary deters cabbage moths, cabbage loopers, and other brassica pests

Carrots

Rosemary repels carrot flies and helps improve carrot growth

Beans

Rosemary attracts beneficial insects that help with bean pollination

Sage

Both Mediterranean herbs have similar growing requirements and complement each other

Thyme

Compatible growing conditions and both help repel garden pests

Lavender

Similar water and soil requirements, both attract beneficial pollinators

Marigolds

Both repel harmful insects and attract beneficial predatory insects

Keep Apart

Cucumber

Rosemary can stunt cucumber growth and affect fruit development

Lettuce

Rosemary's strong oils can inhibit lettuce germination and growth

Pumpkins

Allelopathic compounds from rosemary can reduce pumpkin vine vigor

Nutrition Facts

Calories

23kcal(1%)

Protein

3.15g(6%)

Fiber

1.6g(6%)

Carbs

2.65g(1%)

Fat

0.64g(1%)

Vitamin C

18mg(20%)

Vitamin A

264mcg(29%)

Vitamin K

415mcg(346%)

Iron

3.17mg(18%)

Calcium

177mg(14%)

Potassium

295mg(6%)

Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #172232)

Pests & Disease Resistance

Common Pests

Slugs, snails, carrot rust fly

Diseases

Powdery mildew, root rot in poorly drained soils

Troubleshooting Porto Spineless

What you'll see, why it happens, and what to do about it.

White powdery coating on leaves and stalks, usually showing up mid to late summer

Likely Causes

Powdery mildew — a fungal disease that thrives in warm days and cool nights with poor airflow
Crowded planting at less than 24 inches apart, which traps humidity around the foliage

What to Do

1.Strip and trash (don't compost) the worst-affected leaves to open up airflow
2.Spray a preventive mix of 1 tablespoon baking soda plus 1 tablespoon summer horticultural oil per gallon of water — NC State's Organic Gardening chapter notes this combination works against powdery mildew and should be applied every 3 to 5 days
3.Next season, give plants the full 36-inch spacing so air can move between those 3-to-6-foot stalks

Irregular holes chewed in leaves overnight, silvery slime trails visible on or near the plant base

Likely Causes

Slugs or snails — NC State Extension lists both as common pests on cardoon, and they're especially bad in wet springs or after heavy mulching
Debris and dead leaf tissue sitting on the soil surface, which gives slugs daytime cover

What to Do

1.Clear fallen leaf tissue off the soil promptly — dead plant matter at the base is prime slug habitat and also invites fungal disease
2.Set out iron phosphate bait (Sluggo or similar) around the base of plants at transplant and after heavy rains
3.Hand-pick at night with a flashlight for a week straight — it makes a real dent in the population

Frequently Asked Questions

How long does Porto Spineless cardoon take to harvest?▼

Porto Spineless cardoon typically takes around 100 days from planting to harvest. This timeline allows the stalks and midribs to develop fully and reach optimal tenderness for blanching and cooking. Cool-season growth promotes better quality stalks.

Is Porto Spineless cardoon good for beginner gardeners?▼

Yes, Porto Spineless is excellent for beginners. It's rated as easy to grow and features significantly reduced spines compared to standard cardoon varieties, making handling and harvesting much safer and more pleasant. It's a forgiving plant that thrives in full sun.

What does Porto Spineless cardoon taste like?▼

Porto Spineless cardoon has a flavor similar to artichoke, with a mild, slightly nutty taste. The stalks and midribs are the edible parts and should be blanched before cooking to improve tenderness and reduce bitterness. When properly prepared, they develop a delicate, pleasant flavor.

When should I plant Porto Spineless cardoon?▼

Plant Porto Spineless cardoon in spring after the last frost date in your area. It prefers cool-season growing conditions and requires full sun (6+ hours daily). As a perennial in Zones 6-10, established plants may overwinter in these regions.

How do you blanch Porto Spineless cardoon?▼

To blanch cardoon stalks, tie them up firmly and wrap with black plastic or black-and-white newspaper several weeks before harvest. This blocks sunlight and reduces chlorophyll, resulting in paler, more tender, and less bitter stalks. Blanching is essential before cooking.

Can Porto Spineless cardoon be used as an ornamental?▼

Yes! If left unharvested, Porto Spineless grows 3-4 feet tall and produces striking large purple thistle-like flowers. The sharply lobed, silvery-green leaves make an attractive addition to flower arrangements, making this variety dual-purpose for both food and garden aesthetics.