In the current study, we tested the feasibility of using three species of imported plants to combat desertification in Saudi Arabia. Delonix regia, Jacaranda mimosifolia, and Simmondsia chinensis were chosen for the evaluation because they have previously been reported to have marked drought and heat tolerance characteristics. To examine the feasibility of using these non-native plants for the mitigation of desertification, we aimed to determine the evolutionary relationships between the imported and local plants. DNA extracted from the non-native plants was compared with that of 45 local taxa. Two genes, Maturase K (matK) and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL), were sequenced and aligned for all species of imported and local plants analyzed in this study. The two molecular markers are known to be evolutionary conserved. A molecular phylogenetic tree was generated using the local and imported plants, and it showed similarity between Delonix regia and Cassia senna, indicating that they belong to the same family (Leguminosae). Similarly, Jacaranda mimosifolia (a member of Bignoniaceae) was found to be closely related to the local plants Plantago ovata and P. arenaria. Simmondsia chinensis was determined to be distantly related to many taxa of flora found in Saudi Arabia. The results of molecular analysis and the physiological features of Delonix regia and Jacaranda mimosifolia indicate that both species are closely related to Saudi Arabia flora, more so than Simmondsia chinensis.