As vital carriers of urban culture, historical districts rely on their plant landscapes to play a key role in strengthening the emotional connection between visitors and the site. This study took the Sanfang Qixiang historical district in Fuzhou as a case study, employing a systematic analysis that integrated field surveys, questionnaire interviews, statistical methods, and comparative synthesis. While investigating the characteristics of the plant landscape within the district, the study explored the mechanisms through which eight perceived sensory dimensions of plants influenced visitors’ place attachment. The results showed that: (1) perceived refuge and perceived culture had a significant positive impact on place dependence, while perceived spatiality had a significant positive impact on place identity—each of these three dimensions directly affecting visitors’ place attachment; (2) perceived naturalness, perceived sociality, perceived peacefulness and perceived species richness showed no significant effect on place attachment; and (3) perceived prospect exhibited a significant negative effect on place attachment. The findings suggested that the emotional value of plant landscapes in historical districts stemmed less from ecological abundance or visual openness than from their capacity to define spatial form, create a sense of privacy, and convey regional cultural narratives. Based on these findings, the study proposed optimization strategies such as enhancing spatial layering, improving the quality of sheltered spaces for rest, and activating cultural expression functions, thereby providing both theoretical grounding and practical guidance for landscape renewal and the reinforcement of human–place emotional connections in historical districts.