Mustard greens
Brassica juncea
A fast, erect cool-season annual in the mustard family (Brassicaceae), introduced to all of North America from Eurasia and grown widely as a leafy vegetable. NC State Extension describes a rapid-growing plant about 1-1.5 feet tall and wide with large (over 6 inches) leaves — lobed lower leaves and shorter-stalked upper leaves, smooth with a whitish bloom and sometimes purple veins or fully purple coloring. It does best in the cool of fall and spring and bolts in summer heat, throwing up terminal clusters of small four-petaled yellow flowers and developing a strong, spicy flavor. The leaves, seeds, flowers, and stems are all edible raw or cooked, making it a productive, peppery green for the edible garden.
Edible
Container
Filler
Light
Full sun / Part shade
Water
Consistent moisture
Mature size
12-18" tall · 10" apart
Hardy in zones
Annual; grown as a cool-season leaf crop
AHS heat range
1-6
Plant range authored in AHS heat-zone terms.
Native in Illinois
No
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A productive, peppery leaf vegetable.
Cold hardiness
Future
This plant is grown as an annual; hardiness zones don't apply.
Heat tolerance
Future
Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
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Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Mustard greens (Brassica juncea). Retrieved 2026, June 14, from https://plotwright.garden/plants/brassica-juncea
Sources for every fact
Every fact on this page traces to a source. 18 fields cited - 18 source-backed.
NC State Extension Gardener Plant Toolbox
University extension service
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
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Lifecycle
Regional guidance
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Designer notes