What hardiness zones is Brassica juncea 'Osaka Purple' suitable for?

Brassica juncea 'Osaka Purple' is suitable for USDA hardiness zones 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b.

What are the sun requirements for Brassica juncea 'Osaka Purple'?

Brassica juncea 'Osaka Purple' requires Full Sun.

How much water does Brassica juncea 'Osaka Purple' need?

Brassica juncea 'Osaka Purple' has Medium water needs.

Brassica juncea 'Osaka Purple', Osaka Purple Mustard Greens

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Vegetables

Brassica juncea 'Osaka Purple'

Osaka Purple Mustard Greens

Brassicaceae

Central Asia / Himalayan (B. juncea origin; Osaka Purple from Osaka Japan; smooth round purple leaves; cool-season; baby greens 21 days)

At a Glance

TypeAnnual

HabitUpright

FoliageDeciduous

Height12-18 inches (30-45 cm)

Width12-15 inches (30-38 cm)

Growing Zones

USDA Hardiness Zones

2a - 9b

Zone 2a Zone 2b 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.

What's my zone? →

Frost Tolerancehardy

Key Features

Container Friendly

Maintenancevery low

Overview

Brassica juncea 'Osaka Purple' is an annual leafy green reaching 12-18 inches (30-45 cm) tall with a spread of 12-15 inches (30-38 cm) and an upright, rosette-forming habit. A Japanese mustard green cultivar from the Osaka region, it produces large, round to spoon-shaped leaves 6-10 inches (15-25 cm) long with smooth margins (not frilled)—green with deep purple-red coloring that intensifies in cool weather. The smooth, broad leaves distinguish it from the frilly-leaved 'Red Giant'. Mild mustard flavor when young, becoming more pungent at maturity. Days to maturity 40-50 from direct sow (baby greens in 21 days). Growth rate is fast. Cool-season crop—bolts quickly in heat above 75°F (24°C).

Native Range

Brassica juncea is native to Central Asia and the Himalayan region. 'Osaka Purple' is a Japanese cultivar from the Osaka region.

Suggested Uses

Grown in vegetable gardens for culinary use—salads (baby), stir-fry, braising, pickling. Smooth round purple leaves. Mild when young. Japanese Osaka. Baby greens at 21 days. Cool-season—spring and fall. Purple color intensifies in cold. Bolts in heat. Not suitable for summer growing or where sustained heat exceeds 75°F.

How to Identify

Distinguished from 'Red Giant' by the smooth, rounded (versus frilly, savoyed) leaf margins and the broader, spoon-shaped (versus elongated) leaf form. Distinguished from red cabbage by the loose rosette (versus tight head) habit. Osaka Purple mustard—smooth round purple leaves, Osaka Japan, milder than Red Giant when young, cool-season.

Appearance

Size & Dimensions

Height1' - 1'6"

Width/Spread1' - 1'3"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Four-petaled yellow flowers on stalks 2-3 feet (60-90 cm) when bolting in heat. Bolting makes leaves bitter and tough. Harvest before any flower stalk. Cool-season only.

Detailed Descriptions

Flower Description

Yellow; four-petaled; bolting only

Foliage Description

Deep purple-red over green; smooth round spoon-shaped 6-10 inches; intensifies in cool weather

Growing Conditions

Sun Requirements

Full Sun Partial Shade

Requires 4-8 hours of direct sunlight daily

• 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

Soil Types

loam

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

40-50 days (baby greens 21 days)

Care & Maintenance

Care Guide

Direct sow in early spring 4-6 weeks before last frost, or in late summer for fall harvest. Moist, fertile soil (pH 6.0-7.0). Cool weather intensifies purple color. Succession sow every 2-3 weeks. Days to maturity 40-50 from direct sow; baby greens at 21 days. Bolts quickly above 75°F (24°C). Row cover extends season.