Abstract: Abstract: In the light of a classical symptom of gray-brown leaf margin or scorched patch occurred in vegetative shoot leaf of cut roses mainly planted in Yunnan Province, the study of field survey and indoor test was conducted. The results showed that this symptom was caused by the exorbitant content of available boron in rhizosphere soils or boron in vegetative shoot leaf, the critical values were 3.41 mg/kg and 164 mg/kg, respectively. By comparison with the normal cut roses, the content of N, P, and K in leaf of toxic roses was respectively decreased by 17.7%, 31.1% and 13.9%, however, the content of Mg was rising by 38.4%, and high content of Ca in vegetative shoot leaf was 3.168%, moreover, the value of K/B, Ca/B and Mg/B in leaf was decreased by 65.6%, 66.2% and 51.4%. For the normal or toxic cut roses, the content of boron in leaf was gradually decreased from vegetative shoot to flower shoot, however, the case of K/B, Ca/B and Mg/B was reversed. Therefore, people should attach importance to the balanced fertilization in production of cut roses.