Informants selected for this study were primarily household heads and the main managers of the homegardens. A total of 112 informants were interviewed, with 84 (75.0%) being male and 25 (25.0%) female. These informants were classified into three age groups, as shown in Table 2. We found that the local residents managing the homegardens tended to be older, with half of the informants being over 50 years old, and farmers accounting for 91.1% of the sample.

The survey recorded a total of 152 plant species, encompassing 62 families and 124 genera. Table 3 provides a summary of the homegarden plant species managed by the respondents, including information on their local common names, scientific names, life forms, uses, and plant parts utilized, use method, UV values, RI values, and cultivation status. The enduring management by local residents has fostered a sustainable and resilient traditional homegarden plant system. This traditional practice has been supported by research on homegarden plant diversity in areas like southwestern China, India, and Thailand [3, 36, 37]. This suggests that the long-term management by local inhabitants has fostered a sustainable and resilient traditional homegarden plant system. Several prevalent plant families discovered in these homegardens include Asteraceae (12 species), Cucurbitaceae (9 species), Fabaceae (9 species), Rosaceae (8 species), and Apiaceae (7 species). For example, plants from the Asteraceae and Cucurbitaceae families exhibit high ornamental value while providing additional advantages such as wind resistance, soil conservation, and climate regulation. Fabaceae plants fulfill the dietary requirements of the local population, and notably, they possess robust nitrogen fixation abilities that enhance soil fertility in the karst region of the Laershan Mountains. Our research aligns with a homegarden plant survey carried out in the Sebeta-Awas District of the Oromia Region in Ethiopia. The prevalent plants in local homegardens belong to the Fabaceae and Asteraceae families. These species play a vital role in providing food to assist local communities in addressing food insecurity. [38]. Despite the locals' potential lack of awareness regarding these beneficial functions during field surveys, their significance should not be overlooked.

Based on our survey results, herbaceous plants constituted 56.6% of the total, followed by trees (23.7%), shrubs (12.5%), and vines (7.2%). Herbaceous plants display greater diversity within homegarden ecosystems, potentially attributed to their rapid growth rates, adaptability, and diverse functional attributes that cater to various daily requirements, including medicinal, culinary, and commercial uses. The choice of trees and shrubs may be influenced by economically significant tree species as well as the provision of shade and shelter for housing purposes. Additionally, this composition of life forms among homegarden plants exemplifies the traditional local wisdom pertaining to the sustainable utilization and conservation of plant resources.

The homegarden plants in the Laershan Plateau exhibit rich diversity while also serving various functions and utilitarian values. This study categorizes the homegarden plants into five primary functional types: edible plants, trade plants, ornamental plants, medicinal plants, and forage plants. The data indicate that there are 106 species of both edible and trade plants, signifying that local homegardens in the area mainly serve the needs of food consumption and livelihood maintenance. By classifying various plant types, we can enhance our comprehension of the importance of local homegardens in fulfilling food needs and supporting livelihoods.

These homegardens also play a significant role in planting ornamental plants for aesthetic enhancement and medicinal plants for health purposes. Certain residents plant various ornamental plants in their homegardens to enhance their happiness. Ornamental plants are easily exchanged between gardens. In the survey, a homeowner in "Dehe Village" discovered beautiful Yucca gloriosa in a neighbor's homegarden and transplanted it to their own garden after communication with the neighbor. Medicinal plants play an important role in the Laershan Plateau. For example, Diospyros cathayensis is used to treat sudden heart pain, and many indigenous medicinal plants for injuries, snake bites, and other ailments are distributed in homegardens. Homegarden owners who plant these plants usually have traditional knowledge of treating common local diseases. Homegardens have garnered considerable scholarly interest due to their social and cultural significance. Recently, several studies have offered detailed insights into the cultural roles of homegardens, specifically focusing on the traditional practices of local inhabitants in utilizing and preserving natural resources. These studies highlight the transmission and utilization of indigenous traditional knowledge within homegardens [20, 23, 24, 31].

Additionally, we found 30 species of forage plants for animal consumption that locals can collect for home breeding. Through the investigation, we learned that locals have traditionally used plants grown in gardens as animal feed rather than market feed. They have accumulated abundant plant knowledge, such as the fact that long-term feeding of Galium spurium to pigs can cause toxicity or even death, but short-term feeding is harmless. Therefore, they alternate feeding Brassica rapa and Galium spurium to pigs. Accurate identification and effective use of forage plants demonstrate the wisdom and practical knowledge of local inhabitants in harnessing natural resources and managing animal husbandry. Conducting additional research on the attributes and appropriateness of these forage plants is advantageous in mitigating feed shortages and fostering the sustainable advancement of animal husbandry.

Figure 3 shows the multifunctionality of some plants among the five categories, and we found that Artemisia argyi, Mentha canadensis, and Taraxacum mongolicum are homegarden plants that exhibit all five functions. Most plants have more than two basic functions. The existence of multifunctional plants reflects the unique traditional knowledge of plant utilization held by local residents. The potential for maintaining resilient homegarden ecosystems, cultural heritage, and high-quality homegarden economic development is evident. Hence, there is a critical need to prioritize the optimization of homegarden planning and management to improve their overall efficiency and sustainability. This is particularly important considering the pivotal role of multifunctional plants in supporting homegarden ecosystems, conserving cultural heritage, and fostering economic development [16, 17, 19].

Wayne diagram of plant functional diversity in Miao homegarden on the Laershan Plateau

In addition to descriptive statistics on the multifunctionality of homegarden plants, we evaluate the local utilization of each plant based on its RI value. A higher RI value reflects a greater traditional knowledge of the local community regarding a specific plant. Among the surveyed plants, eight species, namely Mentha canadensis, A. argyi, Elaeagnus pungens, Taraxacum mongolicum, Lindera reflexa, Mirabilis jalapa, Nelumbo nucifera, and Raphanus raphanistrum subsp. Sativus, have an RI value exceeding 1.5. These three plants, M. canadensis, A. argyi, and T. mongolicum, possess all five basic functions (Fig. 4).

JI value of homegarden plants among three townships

The findings highlight the significant traditional knowledge value of these plants in the Laershan region of western Hunan. Our research indicates that these species primarily serve functions related to food provision and sustaining livelihoods. For instance, M. canadensis is predominantly employed for consumption and trade, while A. argyi is also principally utilized for commercial transactions and monetary exchange. This implies that the prioritization of these plant resources by local residents aligns with the region's production methods and living circumstances.

M. canadensis stands out with the highest RI value of 2.00, indicating its wide range of uses and popularity within the local communities. Our investigation uncovered the utilization of its tender shoots and leaves as vegetables or seasonings in a variety of dishes. It is also available for sale in numerous market stalls. Additionally, its beautiful flowers and distinctive aroma are greatly valued. Some residents even brew it as herbal tea to alleviate headaches and cold symptoms. Moreover, it serves as fodder for poultry and livestock. These diverse uses illustrate the deep understanding and extensive knowledge that local residents possess regarding this plant.

A. argyi, with an RI value of 1.75, is also widely employed in various domains, potentially attributed to its traditional medicinal applications and the customs of the Miao ethnic group. Our findings indicate extensive trading of this plant in local markets to meet the distinctive cultural needs of the region. The attentive care given to plants with higher RI values in the homegardens indicates a longstanding tradition of utilizing plant resources, fostering the preservation and advancement of traditional knowledge. It also signifies the local residents' reverence and safeguarding of native plant resources.

The study aims to analyze the practical value of plants in the local area by ranking them according to their UV value. Table 3 shows that Zea mays has the highest UV value (1.43), followed by Ziziphus jujube (1.39). Additionally, Morus alba, Zanthoxylum bungeanum, Brassica rapa, Ipomoea batatas, and Eriobotrya japonica all have a UV value of 1.35, thus ranking them third. Plants with high UV values play a crucial role in the daily life of the local communities. Besides being adaptable and yielding high crops, Z. mays also serves as a staple food source for the locals and a primary feed for livestock. Z. jujube and M. alba fruits are popular and essential components of homegarden planting. Furthermore, Z. bungeanum seeds are utilized as a seasoning in local cuisine, and B. rapa is a crucial ingredient in pickling. The traditional knowledge of plant utilization by local residents helps recognize their practical value better and provides a foundation for the sustainable use of homegarden plants.

The UV value reflects the practical value of plants and their importance within the local communities. Contrasting plants with higher and lower UV values enables us to identify the preferences and demands of the local communities, obtain insights into the current utilization status of local plant resources, and provide references for the selection and promotion of these plants. For instance, although B. vulgaris and A. hookeri are non-essential in the local area, they may be more valuable in other regions. In conclusion, these homegarden plants hold substantial ecological, economic, social, and cultural importance. Similar research work, through ranking plants based on their UV values, allows us to observe the geographical specificity of plant resources in different regions, helping us understand the preferences and needs of local communities [13,14,15, 18]. This approach enables a better comprehension of the role and significance of homegarden plants in local livelihoods.