With the intensification of global climate change and urbanization, extreme rainfall and urban flooding have become increasingly frequent, making the flood tolerance of garden plants a key issue in urban landscaping and ecology. Identifying research progress and development trends in the waterlogging tolerance of garden plants, as well as selecting waterlogging-tolerant species, is a core strategy for advancing urban ecological development. This study employed the Web of Science database to conduct a systematic search using subject, title, and keyword criteria. After excluding irrelevant studies through full-text reviews, 164 articles were selected. Using bibliometric analysis, the research systematically reviewed relevant literature published over the past 21 years on waterlogging tolerance in landscape plants, both domestically and internationally, analyzing research trends and hotspots, while summarizing the physiological and molecular responses of garden plants in flood-prone environments. The research indicates significant differences in flood tolerance among different species of garden plants. The main research directions include morphology, physiology, molecular biology, ecology, cultivation, and species selection, with molecular biology emerging as a key area of development in recent years. Furthermore, in the context of global climate change, this study identifies 50 flood-tolerant plants with high ecological value, and proposes guidelines for selecting flood-tolerant species. It concludes by discussing future research directions in flood tolerance and the potential applications of these plants in urban landscaping, sponge city construction, and ecological restoration.

Flavonoid biosynthesis is proposed to play a critical role in floral organ development in Paeonia species. However, its specific involvement in stamen petalization remains unclear. This study identified and characterized 13 gene families related to flavonoid biosynthesis across four Paeonia species. Comparative and phylogenetic analysis revealed that most flavonoid biosynthesis-related genes experience lineage-specific expansion in P. ludlowii. Genes belonging to the same family were commonly clustered on chromosomes and displayed highly conserved domain and motif compositions. The cis-element analysis identified Cis-acting elements associated with light, hormonal, and stress responses, implicating their regulatory roles in flavonoid biosynthesis. To further investigate the role of these genes in stamen petalization of P. lactiflora, expression profiling analyses were performed on ‘Fen Yu Nu’ (normal stamens) and ‘Lian Tai’ (petaloid stamens) cultivars using transcriptomic data released previously. Three quercetin-related genes revealed distinct stage-specific patterns in ‘Fen Yu Nu’ and ‘Lian Tai’. Notably, PlaF3’H03 exhibited significant upregulation during petaloid stamen development in ‘Lian Tai’, suggesting its role in stamen transformation. Molecular docking identified PlaF3’H07 as a key enzyme with strong substrate-binding affinity (ΔG = −4.7 kcal/mol), supporting its catalytic function in quercetin synthesis. The expression pattern of key flavonoid biosynthetic genes was also confirmed across three developmental stages of floral buds by real-time quantitative PCR. This study provides insights into the genetic basis underlying stamen petalization in P. lactiflora and offers potential targets for genetic improvement of floral traits in Paeonia and other ornamental plants.