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ALLIUM cepa (Aggregatum Group)

Image of Allium cepa (Aggregatum Group)

Jesse Saylor

Family

Liliaceae

Botanical Name

ALLIUM cepa( Aggregatum Group)

Plant Common Name

Scallion, Shallot

General Description

Onions in the Aggregatum Group produce numerous small bulbs rather than a single large bulb. Like other varieties of garden onion (known collectively as Allium cepa), they are biennials that originated in Central Asia but that are unknown in the wild.

The pale- to mid-green, hollow, awl-shaped leaves of these onions arise from clusters of small papery-coated bulbs. Some varieties produce globular heads of greenish-white flowers on upright stems in the summer of their second year. Hot weather may induce first-year plants to bloom (or "bolt"). Many members of this group have sterile flowers which produce no viable seed. The edible flower buds of some shallots are used in salads.

Members of the Aggregatum Group include shallots, which have clusters of numerous slender bulbs; potato onions, with relatively large and few bulbs; and ever-ready onions, grown for their mild-flavored, persistent foliage.

Garden onions are categorized by the day length at which they form bulbs. Some require relatively short days to produce harvestable bulbs; others require long days. Most are planted in early spring and harvested in late summer. In regions with cool but mild winters, they may be planted in fall or early winter for harvest in spring and early summer. Harvested bulbs of Aggregatum Group onions usually store well.

Garden onions require full sun and regular watering because of their shallow roots. Grow them in loose, rich, well-drained soil. Onions in the Aggregatum Group are usually grown from shallowly planted "sets" (small "starter" bulbs). When most of the leaves are in decline and yellowed, dig the bulbs and dry them in a shady well-ventilated place for several days. Clean off any remaining soil and then store the bulbs in a cool, dark, dry spot, where they will keep for months.

Characteristics

  • AHS Heat Zone

    12 - 1

  • USDA Hardiness Zone

    4 - 12

  • 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, Partial Sun

  • Height

    1'-3' / 0.3m - 0.9m

  • Width

    4"-12" / 10.2cm - 30.5cm

  • Bloom Time

    Summer

  • Native To

    Asia

Growing Conditions

  • Soil pH

    Neutral

  • Soil Drainage

    Well Drained

  • Soil type

    Loam, Sand

  • Growth Rate

    Fast

  • Water Requirements

    Average Water

  • Habit

    Clump-Forming

  • Seasonal Interest

    Summer

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    White

  • Foliage Color (Spring)

    Green, Light Green

  • Foliage Color (Summer)

    Green, Light Green, Chartreuse

  • Foliage Color (Fall)

    Green, Yellow Green

  • Fragrant Flowers

    No

  • Fragrant Fruit

    No

  • Fragrant Foliage

    Yes

  • Bark or Stem Fragrant

    Yes

  • Flower Petal Number

    Single

  • Repeat Bloomer

    No

  • Showy Fruit

    No

  • Edible Fruit

    No

  • Showy Foliage

    No

  • Foliage Texture

    Medium

  • Foliage Sheen

    Matte

  • Evergreen

    Semi-Evergreen

  • Showy Bark

    No

Special Characteristics

  • Usage

    Edible, Herb / Vegetable

  • Sharp or Has Thorns

    No

  • Invasive

    No

  • Self-Sowing

    No