Leek (Allium ampeloprasum (Porrum Group)) — Plotwright

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Leek

Habit (mature) · Netha Hussain / Wikimedia Commons · CC BY-SA 4.0

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Leek

Allium ampeloprasum (Porrum Group)

A cool-season onion-family vegetable grown not for a bulb but for its thick, mild, blanched white stalk — a tight cylinder of leaf bases capped by a fan of flat, blue-green, strap-like leaves. A biennial that flowers only rarely in cultivation, leek is grown in U.S. gardens as an annual and gardeners trench or mound soil around the stems to lengthen the sweet white portion. The stalk and leaves carry a delicate, sweet, mild oniony flavor without the pungency of most onions.

Review: Source-backed

Climate fit: moderate (56/100)

Edible

Light

Full sun

Water

Moderate water

Mature size

18-36" tall · 6" apart

Hardy in zones

2a-11b

brutally cold to nearly frost-free winters

Summer heat range

Cool-Mild

cool to mild summers Interim Plotwright tier until the plant AHS range is authored.

Native in Illinois

No

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Cold hardiness

Now

Zone 6b

USDA

Chicago, IL · 1991-2020 average annual coldest day

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Well-suited

2050

Zone 7b

Plotwright

Your zone + climate-model shift · SSP3-7.0 (regional rivalry)

Well-suited

In plain terms: cold winters — coldest nights typically around -3°F.

✓

Well-suited today and still thriving in 2050.

Heat tolerance

°C

°F

Loading current AHS heat-zone and plant heat-fit data at your coordinates…

Where this plant fits

Suitable across 45 ecoregions — 45 climate-resilient through 2070. Best matches first.

Appalachian mixed mesophytic forests

Appalachian-Blue Ridge forests

Arizona Mountains forests

Atlantic coastal pine barrens

Blue Mountains forests

California coastal sage and chaparral

Canadian Aspen forests and parklands

Central Pacific Northwest coastal forests

Central Tallgrass prairie

Central-Southern Cascades Forests

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). Leek (Allium ampeloprasum (Porrum Group)). Retrieved 2026, June 5, from https://plotwright.garden/plants/leek

Sources for every fact

Every fact on this page traces to a source. 18 fields cited — 18 source-backed.

Missouri Botanical Garden PlantFinder

Botanical research database

Backs 17 fields

Identity

Summary

Plant type

Light

Moisture

Hardiness

Heat zone

Size

Spacing

Habit

Design roles

Seasonal interest

Growth stages

Lifecycle

Regional guidance

Success tips

Designer notes

Wikimedia Commons

Photo · CC BY-SA 4.0

Backs 1 field

Image

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The photos above are our reviewed reference set, curated for accuracy.

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