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BRASSICA napus

Image of Brassica napus

Jesse Saylor

Family

Brassicaceae

Botanical Name

BRASSICA napus

Plant Common Name

Rape, Rutabaga, Turnip

General Description

Rapeseed is grown for its oil-rich seed, edible greens and tasty fleshy roots. Its greatest value is its bitter-tasting oil which is used industrially to make biodiesel fuel. Canola oil, which has a mild flavor and is favored for cooking, also comes from a variety of Brassica napus. Some types of rape are grown for animal forage but many are raised for their flavorful greens and large, edible roots. The common name, rape, is derived from the Medieval Latin word rapum, which means turnip.

There are many varieties of rapeseed, many of which have been cultivated in Europe for thousands of years. The types grown for oil seed and forage have thin taproots and are sometimes classified as Brassica napus var. oleifera. Rutabagas or Swedes, grown for the swollen roots and edible greens, are classified as Brassica napus var. napobrassica. The origin of rapeseed is uncertain but believed to be a naturally occurring hybrid between turnip (B. rapa) and kale (B. oleracea Acephala Group). It is now cultivated and naturalized worldwide.

These annual or biennial, cool-season plants have basal rosettes of broad fleshy green leaves with rough hairs and long stems. The leaves may be deeply lobed or violin-shaped. Some varieties form round to oblong fleshy taproots with white or yellow flesh. Tall sprays of bright yellow flowers appear in spring or summer, sometimes in the second season of growth. Elongated seed capsules follow that split open to scatter many reddish-brown to black seeds.

Brassica napus is a cool weather crop that requires full sun and moderately fertile, humus-rich soil with ample drainage. It generally matures in 90 to 120 days after planting depending on variety. The greens can be harvest much earlier. Most varieties are sown early spring before temperatures heat up, in late summer for a fall harvest, or in winter where temperatures are mild. Hot weather or prolonged chilly spells may cause them to flower ("bolt"), which usually results in bitter-tasting, dwindling plants. This species is quite cold hardy and requires minimal fertilization—especially if grown in rotation with nitrogen-fixing legumes.

Characteristics

  • AHS Heat Zone

    9 - 3

  • Sunset Zone

    A1, A2, A3, H1, H2, 1a, 1b, 2a, 2b, 3a, 3b, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24

  • Plant Type

    Vegetable

  • Sun Exposure

    Full Sun

  • Height

    2'-4' / 0.6m - 1.2m

  • Width

    1'-2' / 0.3m - 0.6m

  • Bloom Time

    Spring, Late Spring, Early Summer, Summer

  • Native To

    Europe

Growing Conditions

  • Soil pH

    Neutral, Alkaline

  • Soil Drainage

    Well Drained

  • Soil type

    Clay, Loam, Sand

  • Growth Rate

    Fast

  • Water Requirements

    Average Water

  • Habit

    Clump-Forming

  • Seasonal Interest

    Spring, Summer, Fall, Winter

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    Yellow

  • Fruit Color

    White

  • Foliage Color (Spring)

    Green, Black

  • Foliage Color (Summer)

    Green

  • Foliage Color (Fall)

    Green

  • Foliage Color (Winter)

    Green

  • Bark Color

    Green

  • Fragrant Flowers

    No

  • Fragrant Fruit

    No

  • Fragrant Foliage

    Yes

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    No

  • Showy Fruit

    Yes

  • Edible Fruit

    No

  • Showy Foliage

    Yes

  • Foliage Texture

    Medium

  • Foliage Sheen

    Glossy

  • Evergreen

    No

  • Showy Bark

    No

Special Characteristics

  • Usage

    Edible, Herb / Vegetable, Mixed Border

  • Sharp or Has Thorns

    No

  • Invasive

    No

  • Attracts

    Birds, Butterflies

  • Self-Sowing

    Yes