Horticultural Characteristics of 69 Herbaceous Medicinal Plants as Plant Resources for Agro-Healing Applications

Life form

The selected medicinal plants were classified as either annual or perennial species. Herbaceous annuals complete their life cycle—from germination through flowering, fruiting, and death—within a single year. During unfavorable periods, such as winter or drought, they persist only as seeds. Since they do not naturally re-sprout in the same location the following year, seed collection and replanting are essential for their cultivation. However, they offer the advantage of flowering in the same year they germinate (Korea Forest Service, 2024). Herbaceous perennials, by contrast, live for multiple years. They are defined as “grasses that live for three or more consecutive years; while the aboveground parts die back in winter, the underground organs remain alive,” enabling new shoots to emerge the following spring (Yang, 2018).

Herbaceous annuals can be effectively used in agro-healing programs, enabling participants to clearly observe and directly engage with the processes of growth, flowering, and fruiting within a relatively short period. Horticultural therapy programs, for example, have been reported to encompass activities spanning all stages of plant growth—from soil preparation and seedling planting to watering, thinning, weeding, and harvesting (Oh and Heo, 2021). In contrast, herbaceous perennials, with their extended growth cycles, provide high management efficiency and maintain seasonal continuity, making them particularly valuable for long-term agro-healing programs. In this study, we took into account the characteristics of both life forms to identify plant resources well suited for agro-healing applications.

Family Name

The family names of the selected plants were identified based on the Angiosperm Phylogeny Group IV (APG IV, 2016) classification system and the National Standard Plant List, which together encompass 64 orders and 522 families. Plants within the same family are taxonomically closely related and are likely to share similar morphological and physiological traits, as well as cultivation requirements. Therefore, classifying and understanding plants by family can serve as an effective and systematic approach for plant cultivation and management in agro-healing programs. Furthermore, selecting plants based on taxonomic similarity is expected to enhance management efficiency and provide more practical support for program implementation.

Flowering Season

The flowering season was investigated based on meteorological seasons. Over the past 100 years (1912–2020), Korea has experienced significant changes in the duration of its seasons. Notably, during the most recent 30-year period (1991–2020), summer became the longest season, lasting 118 days, while winter became the shortest, lasting only 87 days. Compared to the earlier period (1912–1940), this represents a 20-day increase in summer and a 22-day decrease in winter. Additionally, the onset of spring and summer has shifted earlier by an average of 17 and 11 days, respectively, while the onset of fall and winter has been delayed by about 9 and 5 days, respectively. Reflecting these climate change trends, this study redefined the seasonal periods as follows: spring (March–April), summer (May–September), fall (October–November), and winter (December–February; Korean Meteorological Administration, 2025). The flowering season of plants is a key factor in determining the operational plans and scheduling of agro-healing programs. In particular, considering the possibility that participants may observe blooming flowers or engage in emotional and aesthetic activities related to flowers, it was deemed more effective to align the flowering season of plants with the operational schedule of the program.

Flower Color

In agro-healing, flower color serves as a representative visual element appreciated by people. While flowers exhibit a wide range of colors, the human visual system can perceive only a limited spectrum, including red, orange, yellow, green, blue, indigo, and purple (Bova, 2004; Majetic et al., 2007; Kim et al., 2023). Colors carry powerful energies that help restore mental and physical balance and stimulate the patient’s inner self, thereby supporting the healing process. Moreover, color influences emotions and physical behaviors, making it an effective tool in treating stress-related conditions. Since each color absorbs different amounts of energy, it has been reported to have beneficial effects even on individuals with visual impairments who cannot perceive colors directly (Yun and Jeon, 2021). In this study, Munsell’s Color System—based on five primary hues: red (R), yellow (Y), green (G), blue (B), and purple (P)—was adopted as the framework for classifying the flower colors of medicinal plants. Munsell’s system was designed to create a balanced and systematic approach to color classification by defining color attributes in terms of hue, value, and chroma, and by emphasizing visual uniformity to clearly distinguish different levels of these attributes (Kuehni, 2002; Minm 2025). Based on this, our study performed a simplified qualitative grouping to enhance visual clarity and analytical efficiency, resulting in a classification system comprising ten distinct color groups.

Harvesting Season

The content of medicinal properties in medicinal plants varies depending on their growth stage. After being cultivated in suitable environments, they are harvested when these properties are at their peak (Kim et al., 2019). However, there is still insufficient standardization regarding the optimal harvesting timing and utilization methods. In actual cultivation settings, cultivation and harvesting often depend on empirical knowledge or local traditions. In this regard, this study conducted a literature review to organize the harvesting seasons of representative medicinal plants, categorized by the specific parts used for medicinal purposes. The seasonal classification of harvesting times was based on previously established criteria for flowering season. Previous research has shown that harvesting is the most favored activity among participants in agro-healing programs focused on horticulture (Jeong et al., 2021). Therefore, this study aimed to support the development of more systematic and practical program operations by aligning harvesting schedules with program planning.

Sowing Season

The sowing season was established with reference to commercially available medicinal plant seed cultivation guides and actual cultivation practices used by farmers. Practical sowing information was compiled by synthesizing various sources, including literature materials (e.g., manuals from the Rural Development Administration), agricultural technology data, and commercial cultivation guidelines (e.g., provided by seed companies). The seasonal classification of sowing season followed the same methodology used for categorizing flowering seasons. The sowing season serves a fundamental factor to scheduling activities in agro-healing programs, where participants are directly involved in planting and managing plants. Setting an appropriate sowing season enhances seed germination rates and early plant growth, enabling participants to more easily observe plant development and changes. Furthermore, effectively planning of the sowing season contributes to the smooth execution of program activities aligned with different plant growth stages, thereby promoting participant engagement and sustained involvement.

Edible Parts

The use of medicinal plants not only as medicine but also as food ingredients is a cultural practice observed globally. In East Asian cultures, concepts such as sik-chi (healing through appropriate food; food therapy), yak-sik-dong-won (medicine and food share the same origin), and yak-seon (medicinal cuisine) highlight the medicinal value of edible ingredients and imply the integration of medicinal plants into daily diets (Kim and Lee, 2020). To assess the potential of each medicinal plant as a food ingredient, this study utilized data from the Food Ingredients Database available through the Korea Food Safety Portal operated by the Ministry of Food and Drug Safety. Plant parts listed as “applicable” in the “Eligibility for Food Ingredients” section of the database indicate their legal approval for use as food ingredients and were therefore selected for this study. When specific restrictions or conditions of use were indicated, these were categorized separately as “Ingredients for Limited Food Use.” Based on this classification, the edible parts of each medicinal plant were further categorized into roots, stems, leaves, flowers, fruits, seeds, and whole plants (i.e., the entire aboveground portion). Previous studies have suggested food therapy activities—such as processing or cooking crops that participants have grown and harvested themselves—as representative components of indoor agro-healing programs (Oh and Heo, 2021). Consistent with these findings, this study considered that clearly identifying the edible parts of medicinal plants would support the planning of food-related activities during program implementation and enhance participant safety by providing accurate information on edibility.

Life form

Among the 69 selected medicinal plants classified by life form, 16 species (23%) were herbaceous annuals, 51 species (74%) were herbaceous perennials, and 2 species (3%) were annual or biennial herbs. This indicates a relatively high prevalence of herbaceous perennials among medicinal plants suitable for agro-healing programs. herbaceous perennials, which continue to grow for several years without the need for reseeding, are more efficient to manage and offer advantages in maintaining seasonal continuity compared to herbaceous annuals. Lee (2015) emphasized the importance of long-term engagement in plant cultivation, stating that “when first starting to grow plants, other activities that provide immediate gratification should be excluded and long-term efforts should be devoted to cultivation.” Lee argued that this cultivation process can have positive emotional effects. Given their ecological characteristics, herbaceous perennials grow in the same location over extended periods. This continuity in both time and space can be considered a structural factor that contributes to the development of emotional stability in program participants by offering a stable and consistent form of environmental stimulation. Therefore, when selecting plant species for such programs, their ecological characteristics should be considered in alignment with the programs’ duration and objectives. A study by Jang et al. (2010) reported that horticultural therapy programs with a greater number of sessions tended to demonstrate higher effectiveness. These findings support the notion that herbaceous perennials, which can be maintained and utilized over extended periods, are suitable and effective materials for agro-healing programs. Specifically, the perennial herbs suggested in this study include root-based medicinal herbs such as Platycodon grandiflorus (Jacq.) A.DC., Panax ginseng C.A. Mey., and Astragalus penduliflorus Lam. var. dahuricus (DC.) X.Y. Zhu. Representative examples also include species primarily used for their leaves or whole above-ground parts, such as Mentha arvensis L. var. piperascens Malinv. ex Holmes and Agastache rugosa (Fisch. and C.A. Mey.) Kuntze (Table 2). In particular, root-based medicinal herbs such as Platycodon grandiflorus (Jacq.) A.DC and Panax ginseng C.A. Mey. exhibit relatively slow initial growth but are characterized by stable and sustained growth over time. In contrast, leafy and herbaceous perennials like Mentha arvensis L. var. piperascens Malinv. ex Holmes and Agastache rugosa (Fisch. and C.A. Mey.) Kuntze produce new leaves and stems each year, offering participants clear and repeated opportunities to observe plant growth and seasonal changes. The specific characteristics of the medicinal plants listed in Table 2 highlight the importance of designing and operating agro-healing programs with a long-term perspective, particularly through the incorporation of herbaceous perennials.

Family Name

Classification of the selected medicinal plants according to the family-level taxonomy of the APG IV (2016) system resulted in a total of 32 families. Among these, Asteraceae represented the largest proportion, comprising 12 species (16%), followed by Lamiaceae with 10 species (14%). Other families that also showed relatively high frequencies included Apiaceae, Brassicaceae, and Cucurbitaceae, each represented by 4 species (6%). This pattern is consistent with previous studies on herbal genetic resources in South Korea. A total of 206 species belonging to 37 families of herbal resources were collected in South Korea, with Lamiaceae (32%) and Asteraceae (19.4%) together accounting for more than half of the total (Park et al., 2019). These findings suggest a tendency toward the preferential use of certain plant families in the composition of medicinal plants utilized in agro-healing. This aligns with the high representation of these two families in the selection of plant species for agro-healing programs. Furthermore, members of the Asteraceae family are commonly consumed as savory vegetables and constitute a significant part of the Korean diet (Choi, 2016). Species such as Aster yomena (Kitam.) Honda, Dendranthema zawadskii (Herbich) Tzvelev var. latiloba (Maxim.) Kitam., Carthamus tinctorius L., and Taraxacum mongolicum Hand.-Mazz. are rich in flavonoids and sesquiterpene lactones, which have been reported to exhibit a range of physiological activities, including antibacterial, anticancer, anti- inflammatory, and antioxidant effects (Son, 2020). The Lamiaceae family is known to be widely used not only as ornamental plants but also as edible delicacies and flavoring agents, as the entire plant body is covered with glandular hairs that emit a distinctive aroma (Song et al., 2002). Therefore, the frequent use of plants from these two families in agro-healing programs (Table 2) may reflect their physiological activities and functional properties.

Flowering Season

The majority of medicinal plants used in agro-healing programs were found to flower in summer, accounting for 62 species (88%), followed by 8 species (12%) that flower in spring. Notably, no species were identified that flower in autumn or winter. These results indicate that a significant proportion of medicinal plants utilized in agro-healing programs bloom during the summer. For agro-healing programs focused on horticultural activities, the use of summer- flowering plants may facilitate visual and olfactory stimulation through their vibrant colors, diverse shapes, and fragrances. The groundcover species most commonly used by horticultural therapy professionals bloomed relatively evenly throughout the year, with 57 species flowering in spring, 52 in summer, 30 in fall, and 24 in winter (Kim et al., 2024). However, these findings are not consistent with those of this study. This discrepancy is likely attributable not only to the selection of plant materials in this study—chosen for their functional properties, such as physiological activity—but also to the concentration of program implementation in the summer, when plant growth and flowering are particularly active. Table 2 lists specific summer-flowering plants, including pot marigold (Calendula arvensis L.), cockscomb (Celosia argentea L. var. cristata (L.) Kuntze), Korean mint (Agastache rugosa (Fisch. and C.A. Mey.) Kuntze), and corn mint (Mentha arvensis L. var. piperascens Malinv. ex Holmes). It also includes spring-flowering species such as Mongolian dandelion (Taraxacum mongolicum Hand.-Mazz.) and violet (Viola mandshurica W. Becker). The seasonal concentration aligned with the blooming period is expected to enhance program efficiency and stimulate greater interest and participation during the corresponding seasons. However, since the plants used in this study primarily bloom in spring and summer, related activities may be limited in the fall and winter. Therefore, future research should consider the full range of seasonal flowering periods and explore additional plant resources suitable for use in the fall and winter, thereby increasing both the diversity and continuity of agro-healing programs.

Flower Color

The plant resources used in this study were categorized into ten color groups. Among them, white-flowered species represented the largest proportion, with 25 species (29%). This was followed by yellow (23 species, 27%), red (14 species, 16%), and purple (13 species, 15%). Purple-blue (PB) accounted for three species (4%), while red-purple (RP) and green-yellow (GY) each included two species (2%). Yellow-red (YR), blue (B), and green (G) were the least represented, with one species each, comprising 1% of the total. As shown in Table 2, representative species in the white category include Mongolian snake-gourd (Trichosanthes kirilowii Maxim.), Korean chrysanthemum (Dendranthema zawadskii (Herbich) Tzvelev var. latiloba (Maxim.) Kitam.), and coastal hogfennel (Peucedanum japonicum Thunb.). The yellow category includes evening primrose (Oenothera biennis L.) and pot marigold (Calendula arvensis L.). A survey of 266 people revealed that women showed the strongest preference for white and yellow cut flowers (Hong, 2005). Hyun (2017) cited the study by Lee et al. (2005), which reported a high level of public preference for yellow cut flowers. These results suggest that the high frequency of white and yellow flowers observed in this study may be advantageous in selecting plant species that reflect the participants’ preferences. Furthermore, Seo and Lee (2013) and Ahn (2015) suggested that the process of recognizing and expressing personal emotions and feelings through color imagery serves a psychological function that promotes self-understanding. The psychological experience of color affects all aspects of the human body, emotions, and cognition. Consequently, it is considered to play a significant role in supporting both mental and physical health, facilitating recovery, and promoting the integration of mind and body. Color is a visual experience and a sensory function of light that cannot be perceived through other senses such as touch, taste, smell, or hearing. However, color perception does not always occur at a conscious level; instead, it is processed within the mind (Holtzschue, 2015; Kim, 2024). Therefore, the floral color characteristics of medicinal plants identified in this study are expected to maximize the emotional effects on participants through visual stimulation in the implementation of future agro-healing programs.

Harvesting Season

A high proportion of medicinal plants were harvested in fall (44 species, 46%) and summer (38 species, 40%). Other plants were harvested in spring (10 species, 10%), winter (3 species, 3%), and throughout all four seasons (1%). Multiple responses were included, as some species could be harvested in more than one season. As shown in Table 2, representative medicinal plants harvested in fall include Korean angelica (Angelica gigas Nakai) and Oriental chaff flower (Achyranthes bidentata Blume var. japonica Miq.), while those harvested in summer include roseroot (Orostachys japonica (Maxim.) A. Berger) and motherwort (Leonurus japonicus Houtt.). These results indicate that the harvesting of medicinal plants is concentrated primarily in summer and fall. This suggests the need for a strategically timed plant acquisition plan and activity schedule that reflect these seasonal harvesting patterns when implementing a healing agriculture program. In particular, designing the program around plant-based materials that are available in summer and fall is expected to enable operation that fully leverages seasonal characteristics. In addition, it has been reported that the medicinal properties and physiological activities of medicinal plants may vary depending on the harvesting season (Kim et al., 2016). Therefore, further research on seasonal variations in these properties and physiological activities, based on the findings of this study, is expected to provide clearer insights into the potential of medicinal plants as agro-healing materials.

Sowing Season

Spring accounted for the highest proportion of sowing seasons, with 54 species (55%), followed by fall (22 species, 22%), summer (14 species, 14%), all seasons (6 species, 6%), and winter (2 species, 2%). Medicinal crops are typically sown or transplanted in spring (RDA, 2018), and this study likewise found that the greatest number of species were sown in spring. As shown in Table 2, representative spring-sown plants include garden balsam (Impatiens balsamina L.), blackberry lily (Iris domestica (L.) Goldblatt and Mabb.), and safflower (Carthamus tinctorius L.). Owen (1994) noted that the act of sowing seeds symbolizes a new beginning and hope, while the subsequent growth process represents opportunities for achievement and change. This suggests that, when selecting medicinal plants with consideration of the sowing season, both the growth cycle and the symbolic meanings of the plants may positively affect participants (Lee et al., 2024).

Edible Parts

Leaves accounted for the largest proportion of edible parts, with 32 species (28%), followed by seeds and young shoots (12 species each, 11%), roots (11 species, 10%), inedible parts (10 species, 9%), and conditionally edible parts (9 species, 8%). A variety of other plant parts were also included, such as stems (4 species, 4%), fruits (5 species, 4%), flowers (3 species, 3%), and sprouts (3 species, 3%). As shown in Table 2, representative medicinal plants with edible leaves include Korean mint (Agastache rugosa (Fisch. and C.A. Mey.) Kuntze), British elecampane (Inula japonica Thunb.), and Bupleurum (Bupleurum komarovianum Lincz.). Plants with edible seeds include brown mustard (Brassica juncea (L.) Czern.) and safflower (Carthamus tinctorius L.). The leaves and roots of these plants are utilized for culinary and medicinal purposes, respectively, and they possess the advantage of being adaptable to diverse forms of processing and application within agro-healing programs. Oh and Heo (2021) noted that modern individuals, accustomed to various convenience foods such as instant meals, may experience healing by engaging with rural cuisine that incorporates fresh produce harvested from vegetable gardens, as well as traditional Korean fermented foods and sauces. This suggests not only the potential of medicinal plants as agro-healing resources, but also their strong applicability in the development of practical food culture programs rooted in the concept of sik-chi, or food therapy—such as medicinal cooking, herbal tea preparation, and seasonal culinary experiences. The specific potential for utilizing medicinal plants with diverse edible parts appears to be closely associated with the therapeutic activity of experiencing rural cuisine, as reported in previous studies.