The plantscapes surrounding historical gardens hold significant value, reflecting the natural pristine state as well as demonstrating the cultural attributes of the landscape. This study aims to develop a method for identifying the characteristics of historic plantscapes and to recognize the authenticity of historic landscapes from the perspective of plant elements. Our method combines textual and geospatial data analysis to examine the plant species, their relationships and combinations, and spatial distribution. The case study focuses on the Beijing suburbs during the Qing Dynasty, as documented in A Collection of Past Events in Beijing. We identified 658 plants recorded, encompassing 44 families and 58 genera. These plants were categorized into 7 groups based on the growth type and morphological characteristics, leading to 54 plant relationship outcomes, 107 plant combination scenarios, 5 plant combination categories, and 7 representative plant combinations. Additionally, we mapped the spatial distribution of plants, forming 16 plantscape groups and depicting the spatial kernel density distribution of important plants. We also determined the characteristics of plantscapes in different directions in the suburb. Our findings advocate for respecting the historical development of the plantscape and understanding its evolution, particularly emphasizing the use of high-quality native plants and plant combinations.