Brassica oleracea 'Calabrese', Calabrese Broccoli
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Annuals

Brassica oleracea 'Calabrese'

Calabrese Broccoli

BrassicaceaeMediterranean

At a Glance

Typeannual vegetable
Habitupright
Foliagedeciduous
Height18-30 inches
Width18-24 inches

Growing Zones

USDA Hardiness Zones

3a - 9b
Zone 3a
Zone 3b
Zone 4a
Zone 4b
Zone 5a
Zone 5b
Zone 6a
Zone 6b
Zone 7a
Zone 7b
Zone 8a
Zone 8b
Zone 9a
Zone 9b
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Container Friendly
Maintenancemoderate

Overview

Brassica oleracea 'Calabrese' is a robust cool-season annual vegetable renowned for producing exceptionally large, dense heads of tightly clustered dark green flower buds. This heritage cultivar typically reaches 18-30 inches in height, forming a sturdy central stem crowned with broad, blue-green leaves that exhibit prominent white veining and a distinctive waxy texture. The signature feature is the substantial central head, which develops as a compact, dome-shaped formation of numerous small flower buds held together in a tight, uniform cluster. The foliage arrangement forms an attractive rosette around the thick stem, with leaves providing natural protection for the developing head. After the main harvest, Brassica oleracea 'Calabrese' demonstrates remarkable productivity by generating multiple smaller side shoots from leaf axils, extending the harvest period significantly. This characteristic makes it particularly valuable for home gardeners seeking extended production from a single planting. The plant's robust constitution and reliable performance have made it a cornerstone variety in vegetable gardens worldwide.

Native Range

Brassica oleracea originates from the rocky coastal regions of the Mediterranean basin and western Europe, where wild forms continue to thrive on sea cliffs and rocky shores. The 'Calabrese' cultivar specifically traces its development to the Calabria region of southern Italy, where it was selectively bred for its superior head size and quality, earning its regional name that persists today.

Suggested Uses

vegetable gardens, container cultivation, succession planting, cool-season crop rotation, fresh consumption, freezing preservation, culinary applications

How to Identify

Brassica oleracea 'Calabrese' is unmistakably identified by its large, dense central head composed of tightly packed dark green flower buds forming a characteristic dome shape. The robust stem supports distinctive blue-green leaves with pronounced white veining and a waxy surface texture that distinguishes it from other brassicas. Unlike modern hybrid varieties, Brassica oleracea 'Calabrese' typically produces one prominent central head measuring 6-8 inches across, followed by numerous smaller secondary heads. The overall plant architecture is more open than compact varieties, with leaves extending outward from the central stem in a rosette pattern.

Appearance

Size & Dimensions

Height1'6" - 2'6"
Width/Spread1'6" - 2'

Colors

Flower Colors

yellow

Foliage Colors

blue
green

Bloom Information

Bloom Period

J
F
M
A
M
J
J
A
S
O
N
D
SpringSummer
late spring to early summer if not harvested for heads

Detailed Descriptions

Flower Description

small yellow flowers if allowed to bolt

Foliage Description

blue-green with prominent white veining

Growing Conditions

Sun Requirements

Full Sun
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.0(Neutral)
357912
Drainage
moist

Water & Climate

Water Needs

moderate to high

Frost Tolerance

hardy

Time to Maturity

60-90 days

Care & Maintenance

Care Guide

Brassica oleracea 'Calabrese' thrives with consistent moisture and cool growing conditions, requiring deep, regular watering to maintain evenly moist soil throughout its development. Apply a balanced fertilizer at transplanting, followed by side-dressing with nitrogen-rich fertilizer three weeks later to support robust head formation. Mulching around plants helps retain soil moisture and suppress competing weeds while moderating soil temperature. In regions with intense summer heat, provide afternoon shade or plant for fall harvest to prevent premature bolting. Monitor regularly for common brassica pests including cabbage worms, aphids, and flea beetles, employing row covers during vulnerable early growth stages.

Pruning

Brassica oleracea 'Calabrese' requires minimal pruning during active growth, with maintenance limited to removing yellowing or damaged lower leaves as they appear. After harvesting the main head, cut the central stem at a 45-degree angle approximately 6 inches above ground level to encourage the development of secondary side shoots. These smaller heads will continue producing for several weeks, significantly extending the harvest window. Remove any premature flower stalks that begin developing before head maturity to redirect the plant's energy back into head formation rather than seed production.

Maintenance Level

moderate

Container Growing

✓ Suitable for container growing

Minimum container size: 5 gallons

⚠️ Toxicity Warning

Brassica oleracea 'Calabrese' is completely non-toxic and safe for human consumption, with all plant parts including heads, leaves, stems, and flowers being edible and nutritious. The plant poses no toxicity concerns around children or pets, though consuming large quantities may cause mild digestive upset in some animals due to the high fiber content and natural compounds found in brassica vegetables.

Planting Guide

Planting Methods & Timing

Planting Method

transplant

Indoor Start

6 weeks before last frost

Direct Sow Timing

early spring, 2-3 weeks before last frost date

Days to Maturity

60–90 days

Plant Spacing

18 inches

Companion Planting

Good Companions

lettuce
spinach
onions
garlic
carrots
beets
herbs
marigolds

Avoid Planting With

tomatoes
peppers
strawberries
pole beans
Brassica oleracea 'Calabrese' (Calabrese Broccoli) - Identification & Care Guide | PlantRef