Norman, OK Invasive Plant Rules: Prohibited Species (2026)

Chapter 6 of the Norman Code of Ordinances amends the International Residential Code to add Section R328, Landscape Requirements, effective for building permits issued for new residences within urban residential plats since May 12, 2008. 1 requires at least one tree per single-family or two-family lot, two trees on lots larger than 10,000 square feet, and one tree per street frontage on corner lots. Trees must be at least two-inch caliper, measured six inches above grade, and cannot sit in utility easements or the intersection sight triangle defined by the City Engineering Design Criteria.

1 sends applicants straight to Appendix D, the city's Plant List, and limits the pool to Section B, the species that 'DO MEET' Norman's climate and soil requirements. Appendix D Section A is the mirror list: species that 'DO NOT MEET' those cultural characteristics. Two of the Section A entries are marked, in the code's own words, 'Invasive species. Will survive any condition': Ailanthus altissima (Tree-of-Heaven) and Broussonetia papyrifera (Paper Mulberry). 1 only authorizes Section B species, a builder cannot count either invasive tree toward the mandatory planting, no matter how well it would survive Norman's soil and drought conditions.

The rule reaches only the code-mandated street and lot trees tied to a new building permit; it does not order removal of Tree-of-Heaven or Paper Mulberry already growing on established lots. Species identification tags must stay on the newly planted trees until the certificate of occupancy is issued, giving city inspectors a direct way to confirm the species matches Section B before signing off.