Enter your ZIP to see whether this is legal to plant in your state, and whether it survives your winter.
No.
Leyland cypress is highly flammable and does not belong near structures.
Three sources advise against it. The USDA Forest Service’s eastern plant selector gives Leyland cypress its lowest Firewise rating, “Not Firewise,” describing it as a fast-growing screen in hot, dry, sunny locations and very susceptible to bagworms. Virginia Cooperative Extension assigns it H, the avoid rating on its three-point flammability scale, while noting that it tolerates drought, poor fertility, salt spray, and extreme soil pH.
British laboratory testing reaches the same practical conclusion. The Dorset Heaths Partnership, Firewise UK, and the University of Exeter place Leylandii in their red class. Their guidance warns that dead, dry material can produce flames higher than 2.5 metres and advises against putting the tree directly beside a home or shed.
One whole-plant study by the USDA Forest Service and NIST rated it moderately flammable rather than highly flammable. That result comes from large-scale burns and places the plant in the middle of that study’s three groups. It adds nuance, but it does not outweigh the repeated avoid ratings, including the British laboratory result. For a tree that reaches about 25 feet at maturity, separation from buildings and removal of dead, dry material are the prudent response.
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 DC, DE, MD, NJ, OH, PA, 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 6 · single-value meaning unresolved · whole zone precision · source stated
Source taxon: X Cupressocyparis leylandii · 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 3 — 10–30 ft from the structure; thin vegetation, remove debris, and minimize plant massing [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.
