Cold hardiness

Future

2050

2100

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

USDA

Published baseline for this location from 1991-2020.

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

Well-suited

2050

Zone 7a

Plotwright

Projected zone for this same location in 2050 (2041-2070) using SSP3-7.0 (regional rivalry).

Well-suited

In plain terms: This location is in Zone 6b today. Its hardiness profile is cold winters, and coldest nights are typically around -3°F. By 2050, the projected hardiness zone is Zone 7a based on SSP3-7.0 (regional rivalry). That is a +0.5-zone shift from Zone 6b to Zone 7a by 2050.

✓

Well-suited today and still thriving in 2050.

Heat tolerance

Future

2050

2100

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.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 40 ecoregions — 35 climate-resilient through 2070 · 5 suited today. Best matches first.

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Arizona Mountains forests

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Blue Mountains forests

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Canadian Aspen forests and parklands

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Central Pacific Northwest coastal forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

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Colorado Rockies forests

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Cross-Timbers savanna-woodland

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What it needs

Conditions

Light

Full sun / Part shade

Water

Moderate water

Spacing

42"

Habit

Clump-forming herbaceous perennial vegetable

Care tips

•

Do not harvest the first year - let the crown establish, then take only the thickest stalks in year two (Missouri Botanical Garden PlantFinder).

•

Snap off the whitish flower stalks as they appear so energy goes into the edible petioles.

•

Never eat the leaf blades - they are toxic; only the stalks are food.

Lifecycle

Planting

Plant in fertile, sandy-humusy, slightly acidic, medium-moisture, well-drained soil in full sun to part shade. Propagate via root (crown) divisions in early spring, spacing them 3-4 feet apart (Missouri Botanical Garden PlantFinder).

Transplanting

Move dormant crown divisions in early spring before growth resumes; site at the garden periphery or in a border where the roots can stay undisturbed for years.

Early growth

Maintain consistent moisture and remove flower/seed stalks promptly so energy goes to the crown. Avoid harvesting until year two so the crown can establish (Missouri Botanical Garden PlantFinder).

Maturity

Mature plants reach about 2-3 feet tall and 3-4 feet wide with dark green heart-shaped foliage and red-to-green edible stalks; whitish flowers appear in terminal panicles May through late summer. Refresh (divide) root crowns every 3-4 years.

Propagation

Root-crown division in early spring is the standard method, keeping at least one bud per division; this also rejuvenates aging crowns.

Pollination

Pollination not applicable

Rhubarb is grown and propagated as a vegetable from root-crown divisions, not from pollinated seed, so fruit/seed pollination is not part of normal garden culture. Gardeners are in fact advised to remove the whitish flower panicles (Missouri Botanical Garden PlantFinder) so the plant directs energy into the edible stalks rather than flowering and setting seed.

For people

Parts edible

Only the leaf stalks (petioles) are edible - the tart red-to-green stalks used in sauces, jams, and pies. The leaf blades contain toxic levels of oxalic acid and must never be eaten (Missouri Botanical Garden PlantFinder).

Edible parts

leaf stalks (petioles)

Toxic parts

leaf blades

Native range

AHS heat range

1-6

Climate notes

•

Missouri Botanical Garden PlantFinder lists rhubarb (profiled under the synonym Rheum x hybridum) for USDA zones 3 to 8 in full sun to part shade with medium water, 2-3 feet tall and 3-4 feet wide.

•

Missouri Botanical Garden PlantFinder notes performance declines in hot, humid summer climates; rhubarb is a cool-climate crop that needs a winter chill period and resents prolonged heat.

•

Tolerates cool to mild summer heat - rhubarb is an Old World (Asian) cool-season cultigen, not native to North America; the Missouri Botanical Garden PlantFinder zone 3-8 ceiling reflects declining performance in hot, humid summers rather than reliable Hot/Extreme-tier tolerance.

In the designer

Growth over time

24-36" tall · 36-48" spread

Mature productive clump with full stalk yield and bold foliage.

Design roles: Edible · Structure · Focal point

Seasonal interest

Spring

Summer

Fall

Winter

Filled = the plant has seasonal interest · ▾ now = your current season

Rhubarb

At a glance

Related products

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

For people

Native range

Climate notes

In the designer

Seasonal interest

Sources & citations