roundleaf greenbrier
Smilax rotundifolia
A genus split is not a placement verdict.
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Roundleaf greenbrier has conflicting fire-resistance findings, so it cannot be called reliably resistant.
Virginia Tech’s extension service gives this vine an L, the favorable end of its three-point flammability scale for Virginia landscapes. That expert-curated assessment recommends it from a firewise standpoint, while also describing the plant as weedy and invasive and noting that evergreen forms exist. The rating applies within a regional guide rather than a laboratory test.
A 2007 study in the International Journal of Wildland Fire points the other way. After conditioned foliage and twigs were exposed to 25 kilowatts per square meter in a cone calorimeter, the authors placed roundleaf greenbrier among plants with high effective heat of combustion. That measure concerns heat released during burning, not a complete judgment about a living vine in a yard. A related trait database reports a leaf calorific value of 3,630.46 kilocalories per kilogram, but sets no threshold that turns this number into a resistant or hazardous rating.
The sources use different methods and scales, and neither result cancels the other. Virginia’s landscape guidance offers some reassurance, but the high laboratory finding prevents a firm fire-resistant label. Near a home, roundleaf greenbrier is best treated as an uncertain choice rather than assumed to be reliably resistant.
- Form
- vine
- Mature height
- ~1 ft
- Water need
- moderate
- Rated in
- Global; Virginia / Mid-Atlantic; north-eastern and mid-Atlantic United States
