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Russian arborvitae is a poor near-house fire choice in the Eastern US selector, despite its LZ2 placement label.
The historical Microbiota decussata row pairs NOT Firewise with Landscape Zone 2. LZ2 means 5 to 10 feet from a house; the zone guidance also says to avoid evergreens that ignite easily and burn quickly. These entries do not combine into a clear favorable planting recommendation. Reading the distance alone would discard the source's adverse grade.
The row describes a spreading conifer, records ladder potential without pruning, and marks it noninvasive. Its note says sun or shade, although the separate exposure field says full sun. Adaptable soil pH, low tolerance of poorly drained soils and medium drought resistance are site characteristics, not evidence that shade or irrigation reverses the fire grade.
Applying its framework to high-fire-risk sites, the program calls within LZ2 for a well-kept lawn and fuel breaks made with features such as paths, walls or patios. Trees there need clearances of at least 10 feet from the house both vertically and horizontally at maturity, with 10 to 15 feet between crown edges; these tree rules do not prescribe spacing between Russian arborvitae shrubs. Continued watering, pruning, dead-leaf and twig removal, and pruning of dead, diseased or low branches accompany horizontal and vertical separation. None of those maintenance instructions resolves the row's conflicting placement and fire labels.
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: Microbiota decussata · 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] (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.
