Plant interactions influence species distribution in an ecosystem. These interactions may be related to phylogeny because close relatives might grow apart due to stronger competition. Physical traits, such as size, may also influence species distribution. We tested whether woody plants from phylogenetically distant species grow closer to each other than phylogenetically closer ones in desert scrubland, pine-oak forest, and thornscrub in northeastern Mexico. The study was carried out using nearest neighbor physical distances. Plant crown diameter was tested for correlation with physical distance to neighbor plants to see if plant size influenced distance to neighbor individuals. Phylogeny did not correlate with physical distance between plants. Crown diameter was correlated with physical distance to the nearest neighbor only in desert scrubland. Our hypothesis of greater physical distance between closely related species was not supported by our results, and the opposite was found for 20% of the species studied.