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Red horsechestnut receives a low-flammability rating in Ohio and a more qualified “Moderately Firewise” judgment in an eastern plant selector.
The eastern recommendation includes placement and pruning conditions.
Ohio State’s guide identifies Aesculus x carnea and describes it as somewhat stress tolerant and slow growing. Its low rating and the Eastern United States Fire Performance Plant Selector’s qualified category are separate regional judgments, not interchangeable fire-test results.
The eastern selector assigns this hybrid to LZ3, its area 10 to 30 feet from a house. Within that guidance, remove debris and thin vegetation for 30 feet; on slopes, extend clearing and thinning to 100 feet downhill. For trees, it specifies a minimum of 10 to 15 feet between crowns. Choose accompanying shrubs and groundcovers for their mature height, limit massed planting, and mow brush and weeds annually. Terracing steep slopes may slow spread, with the benefit depending on wind and available fuel.
The selector also flags ladder potential without pruning. Watering, removal of dead material and pruning remain necessary parts of its landscape guidance. These are the eastern program’s conditions; they do not establish a universal setback or make the tree incapable of burning.
There is a separate planting disagreement to resolve locally. The Pacific Northwest extension profile describes this exact hybrid as non-invasive, while the eastern selector marks invasive potential. The Northwest profile also warns that its spiny fruits are poisonous to horses, dogs and cats. A favorable flammability category settles neither invasive suitability nor that fruit hazard. Confirm the hybrid’s identity and local suitability before selecting it for the space allowed by the applicable landscape guidance.
Form
tree
Rated in
OR/WA/ID; Ohio / Midwest; Pacific Northwest (Oregon / Washington / Idaho); eastern US
On this lot
1. Fire evidence and conditions
Fire evidence
Fire-resistant — location does not change the cited classification.
Ohio State University Extension Bulletin 921 is an Ohio publication that describes Ohio fire seasons and landscape conditions and labels nativity to Ohio. FireApproved publishes 352 exact source-owning plant records from its eight rated tables. This historical publication scope does not assert current extension endorsement or that a listed plant suits every Ohio site.
The October 2023 joint Pacific Northwest Extension publication explicitly names Oregon, Washington, and Idaho and publishes more than 150 plant profiles. FireApproved has normalized 155 exact plant records from the source; publication scope does not assert that every listed plant suits every site within the three states.
2. Why this plant is relevant here
State distribution
Documented in ID, OR, WA.
Native range
Introduced / established
USDA hardiness
Documented range 4–9.
3. Legal, ecological, and broader status
Legal-list status
Seed-list status
Reported invasive here
Broader regional context
Federal context
How to read this page
The status above is computed from the cited rows below: independent recommendations can support a fire-resistant result, an avoid row can produce keep-away, and disagreement stays visible as conflict. Placement notes preserve each source’s own scheme rather than translating unlike rules into one scale. This is evidence about a plant, not permission to plant it in every part of the defensible space; Zone 0 remains noncombustible.
Plant hardiness evidence
These values describe the plant source. Your ZIP zone comes from the separate 2023 USDA
Plant Hardiness Zone Map. Whole-zone values stay whole-zone, and a single unresolved value
is not treated as a tolerance range. Different source boundaries stay separate: overlapping
statements are compared independently, while only ranges with no shared zone are called a conflict.
Source prints 5 · single-value meaning unresolved · whole zone precision · source stated
Source taxon: Aesculus x carnea · exact match.
Source location: Cold Hardiness Zone field in the recovered selector record.
Not used for comparison: The recovered selector prints one Cold Hardiness Zone value but does not define it as a minimum threshold or a one-zone range.
4–9 explicit range · whole zone precision · source stated
Source taxon: Aesculus x carnea · exact match.
Source location: Red horsechestnut profile, USDA hardiness zones field.
Where its sources say to plant it
Placement rules below use each source's own distances or named zones, tied to its rating.
They are not interchangeable with the directory's current Zone 0 guidance.
Eastern United States Fire Performance Plant Selector: Landscape Zone 3 — 10–30 ft from the structure; thin vegetation, remove debris, and minimize plant massing [Fire Performance Plant Selector landscape zone] (mid-scale rating)
Fire-resistant plant profile galleries: Red horsechestnut — Aesculus x carnea [osu-2023-trees-gallery] (with its recommendation)
The evidence
Grouped by what each source concluded. Primary evidence rated the plant itself
(a lab, field program, or original curation); corroboration compiled or
republished another source's rating and resolves to its root lineage.
