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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
Loading current AHS heat-zone and plant heat-fit data at your coordinates…
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 cited18 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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