A bacterial strain, designated CJ1-R5(T), was isolated from the flower of the royal azalea plant (Rhododendron schlippenbachii) collected in Jeju Island, Republic of Korea. The strain was a Gram-negative, strictly aerobic, motile, rod-shaped bacterium, growing at a temperature range of 4-33 degrees C (optimum 28-30 degrees C), pH 5.0-9.0 (optimum pH 7.0-8.0), and 0-1% NaCl (optimum 0%). The 16S rRNA sequence analysis of strain CJ1-R5(T)revealed the highest sequence similarity (97.9%) withXylophilus ampelinusATCC 33914(T), and sequence similarities of less than 97.2% with other validly named species. Phylogenetic tree analysis based on the 16S rRNA gene sequences showed that strain CJ1-R5(T)clustered withXylophilus ampelinusATCC 33914(T)and two uncultured bacterial clones. The only quinone observed in strain CJ1-R5(T)was ubiquinone-8. The polar lipids observed were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid and two unidentified lipids. The major fatty acids were C-16:0, C(17:0)cyclo, and summed feature 8 (C-18:1 omega 7cand/or C-18:1 omega 6c). The genome size of strain CJ1-R5(T)was 5.85 Mbp. The genomic G + C content was 68.4 mol%. ANI and dDDH values between strain CJ1-R5(T)andXylophilus ampelinusATCC 33914(T)were 79.0% and 22.5%, respectively. Based on the polyphasic taxonomic data, strain CJ1-R5(T)is considered to represent a novel species, for which the nameXylophilus rhododendrisp. nov. is proposed. The type strain is CJ1-R5(T)(= KACC 21265(T) = CCTCC AB2020030(T))