needle and thread

Idaho Firewise gives the grass a fire-resistance score of 1 out of 10. Its field-trial scale connects each score to planting distance: 10 is acceptable at 10 feet from a structure, while 1 means keeping the plant at least 100 feet away. That finding comes from southern Idaho and the Intermountain region and supports a clear warning.

The University of Arizona Cooperative Extension reaches the opposite practical conclusion for Arizona above 3,000 feet. Its 2011 revision lists needle and thread among FIREWISE plant materials. This is a compiled, binary system covering groups of trees, grasses, and shrubs, so inclusion amounts to a recommendation rather than a position on a ten-point scale.

The disagreement sits between a field-trial score tied to distance and a compiled list limited by elevation, with each source addressing a different region. Needle and thread is a grass in the Poaceae family, native across the southwestern, northwestern, north-central, and northeastern United States. For placement near a building, the specific 1-of-10 score carries the stronger caution: regard the plant as highly flammable and keep it at least 100 feet from structures.