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Crossvine should be treated as highly flammable and kept away from structures, despite one favorable Virginia rating.
Four services warn against it. The USDA Forest Service and state Firewise programs place crossvine at “Not Firewise,” the least favorable point on their four-part scale. North Carolina’s extension sources are firmer: the 2005 assessment called it extremely flammable, while the 2025 revision and current Plant Toolbox classify it as highly flammable. The newer wording reflects a changed scale that dropped the extreme category, not proof that the vine became safer.
Virginia Cooperative Extension provides the conflict. It gives crossvine an L rating on a three-point scale of how fire-prone plants are, placing it among the recommended choices. Regional setting and rating design may help explain why Virginia’s judgment differs from the eastern and North Carolina assessments, but they do not reconcile the conclusions.
Idaho Firewise adds a fire-resistance score of 6 out of 10. That score falls within the mixed range under the thresholds used with its planting-distance scale, so it does not overturn the stronger warnings. Crossvine is a sun-loving vine in the Bignoniaceae family that reaches about 25 feet at maturity. Given its size and the repeated high-flammability findings, the prudent reading is to keep it away from structures rather than rely on the lone favorable rating.
Southern Idaho (ID footprint); partial normalized coverage · 2013-11-08
The official database labels itself "For Southern Idaho" and describes Idaho residents at the urban-rangeland interface. FireApproved publishes 419 existing plant owners that cite its scored rows. This bounded Southern Idaho scope is regional context, not statewide coverage or a conclusion that the score transfers unchanged to every Idaho site.
The complete three-table AG-874 plant list is explicitly for North Carolina and contains 202 low-, medium-, or high-flammability rows. FireApproved accounts for all source rows under its strict taxonomy and lineage rules; source scope does not establish local suitability at a particular North Carolina site.
Virginia Cooperative Extension's publication opens with Virginia wildfire conditions, identifies its Virginia Firewise Landscaping Task Force, and labels plants native to Virginia. FireApproved publishes 306 exact source owners. Publication scope does not establish parcel suitability or current endorsement of this archived 2009 list.
2. Why this plant is relevant here
State distribution
Documented in AL, AR, DC, DE, FL, GA, IL, IN, KY, LA, MD, MO, MS, NC, NJ, OH, OK, PA, SC, TN, TX, VA, WV.
Native range
Current cited native range in AL, AR, FL, GA, IL, IN, KY, LA, MD, MO, MS, NC, OH, OK, SC, TN, TX, VA, WV.
Introduced / established
USDA hardiness
Only uncertain or inapplicable hardiness rows are cited; no primary zone is projected.
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.
Native and introduced range evidence
These are exact U.S. botanical-area records from the cited range source. Native and
introduced describe biogeographic relationship, not fire performance or planting approval.
Doubtful and extinct rows stay visible but do not count as current presence.
The lossless worldwide derivative is retained once in the research corpus; object pages repeat only exact U.S. areas needed by the local lens. The JSON twin carries the same page assertions.
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: Bignonia capreolata · 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.
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 4 — beyond 30 ft; outside the selector's recommendation area [Fire Performance Plant Selector landscape zone] (with its avoid rating)
Fire Resistance of Plants Master Database: plantable at 50' from home [Idaho minimum planting distance] (mid-scale rating)
North Carolina Extension Gardener Plant Toolbox: bignonia-capreolata [nc-toolbox-flammability-facet] (with its avoid rating)
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.
