Border forsythia (Forsythia × intermedia) — Plotwright

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Border forsythia

Habit (mature) · Jerzy Opioła / Wikimedia Commons · CC BY-SA 4.0

Limited coverage

Border forsythia

Forsythia × intermedia

A deciduous shrub grown almost entirely for its explosion of yellow four-lobed flowers that line the bare arching stems in early spring, before the leaves emerge. A garden hybrid of two Asian species (Forsythia suspensa × F. viridissima) — not native to North America. Missouri Botanical Garden describes it as a "one-season wonder" that fades into the background after bloom, so it earns its place as a late-winter color signal rather than a four-season anchor.

Review: Source-backed

Climate fit: narrow (38/100)

Focal point

Structure

Border

Light

Full sun / Part shade

Water

Moderate water

Mature size

72-120" tall · 96" apart

Hardy in zones

5a-8b

very cold to frosty winters

Summer heat range

Cool-Warm

cool to warm 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 40 ecoregions — 34 climate-resilient through 2070 · 5 suited today · 1 newly possible by 2070. Best matches first.

Appalachian mixed mesophytic forests

Appalachian-Blue Ridge forests

Arizona Mountains forests

Blue Mountains forests

Canadian Aspen forests and parklands

Central Pacific Northwest coastal forests

Central Tallgrass prairie

Central-Southern Cascades Forests

Colorado Rockies forests

Cross-Timbers savanna-woodland

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). Border forsythia (Forsythia × intermedia). Retrieved 2026, June 5, from https://plotwright.garden/plants/forsythia

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

Community photos

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

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