Enter your ZIP to see whether this is legal to plant in your state, and whether it survives your winter.
Hardy orange is rated fire resistant, with four sources reaching favorable conclusions under different rating systems.
Virginia Cooperative Extension gives it “L,” the favorable end of its three-point flammability scale. Kyoritsu Shuppan puts hardy orange in its large fire-protection-power class. Kagoshima Prefecture, which reproduces the classification, describes ember interception as one way highly fire-protective trees can help; they can also slow fire spread and promote upward dispersal of heat and smoke. Maryland, New Jersey, and West Virginia forestry agencies call it relatively resistant to fire and more resistant to wildfire ignition.
The USDA Forest Service and state Firewise programs offer the most restrained judgment: “Moderately Firewise,” or 2 on a four-point scale where 1 is the strongest rating. That is not a contradiction. The sources use different scales, and the multistate list does not publish a comparative scale or a row-by-row method. Even so, every source places hardy orange on the favorable side, while differing over how strongly to state the result.
Hardy orange is a roughly 15-foot tree in the citrus family that grows in full sun and is hardy to USDA zone 5a. Its thorny stems call for care during handling, but its adaptability to different soils can make placement easier. Taken together, the findings support calling hardy orange fire resistant, with “moderately Firewise” serving as a useful reminder that the rating is favorable rather than absolute.
Form
tree
Mature height
~15 ft
Light
Full sun
Rated in
Japan; Maryland, New Jersey, and West Virginia; Virginia / Mid-Atlantic; eastern US
On this lot
1. Fire evidence and conditions
Fire evidence
Fire-resistant — location does not change the cited classification.
Maryland Forest Service says the list contains plants that can be grown in Maryland and identifies Maryland natives. FireApproved publishes 169 exact source owners from the 180 printed rows; an unrepresentable form and duplicate-owner rows are not broadened. The list calls itself non-comprehensive and does not establish suitability for every Maryland site.
NJ; partial normalized coverage
New Jersey DEP publishes a state edition saying the listed plants can be grown in New Jersey and are relatively resistant to fire. Its same 180 printed taxon occurrences map to the 169 conservative owners already normalized for the template family. The list is non-comprehensive and does not establish suitability for every New Jersey site or override the Pinelands Commission's separate placement and fuel-break rules.
WV; partial normalized coverage · 2026-08-26
West Virginia Division of Forestry publishes a state edition saying the listed plants can be grown in West Virginia and are relatively resistant to fire. Its same 180 printed taxon occurrences map to the 169 conservative owners already normalized for the template family. The list is non-comprehensive and provides no comparative or site-specific rating.
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, LA, MD, MO, MS, NC, NJ, OH, OK, PA, SC, TN, TX, VA, WV.
Native range
Introduced / established
1 sourced range or established record. This is not an invasive warning.
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.
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: Poncirus trifoliata · 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 2 — 5–10 ft from the structure; maintained lawn or fuel breaks, with easily ignited evergreens avoided [Fire Performance Plant Selector landscape zone] (mid-scale rating)
Tree fire-protection classification in Hito to Shinrin: カラタチ — Table 10-2 [tadaki-kira-1982-fire-protection-power] (with its recommendation)
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.
Tree fire-protection classification in Hito to Shinrin (人と森林) — Kyoritsu Shuppan; table reproduced by Kagoshima Prefecture · Hito to Shinrin (1982), Table 10-2; Kagoshima web reproduction · original sourcePrimary evidenceExpert-curatedlineage: independent (root of Japanese municipal fire-protection tree lists)
Table 10-2 prints カラタチ in the large fire-protection-power class. The Kagoshima reproduction says highly fire-protective trees can slow spread, promote upward dispersal of heat and smoke, and intercept flying embers.
Listed as Poncirus trifoliata (Hardy-Orange). The source says listed species exhibit stronger resistance to ignition by wildfires. Source comments: Has thorny stems. Soil adaptable
