Study on Garden Tree Species Usable as Cut Flowers: Focusing on Woody Plants
Article information
Abstract
Background and objective
This study analyzed woody plants among native garden tree species in South Korea that can be utilized as cut flowers, aiming to address the limited use of indigenous garden plants in the floral market. The research was motivated by the reliance of most cut flowers on naturalized plants introduced from foreign countries. Given the diverse climate and vegetation in South Korea, it is essential to evaluate the potential of native garden plants for floral applications, thereby enhancing the self-sufficiency and sustainability of the floral industry.
Methods
The study investigated 367 garden tree species based on seven plant guides, and derived cut flower criteria through literature review, in-depth interviews with experts, and a survey. The usability of the four elements of garden tree species, including flowers, leaves, branches, and fruits, was analyzed. To this end, the data was analyzed using a Likert scale and descriptive statistics.
Results
Of the 367 garden tree species studied, excluding the 297 species already utilized in the cut flower market, 60 of the remaining 70 species were assessed as having significant potential for use as cut flowers. Among these, 12 species were identified as highly suitable for three material categories: flowers, leaves, branches, and fruits—while 19 species exhibited potential in two categories, and 27 species were deemed suitable for one category. Notably, Malus sieboldii and Deutzia gracilis Siebold and Zucc., which demonstrated suitability across all four categories, exhibited exceptionally high potential as materials for cut flowers.
Conclusion
This study identified 60 woody plants that can be used as cut flowers among garden tree species, thereby confirming the potential of garden plants in the floriculture industry. Future research will be able to provide more specific guidelines for the commercial use of garden plants and contribute to establishing practical distribution strategies.
Introduction
Most flower decorations use cut flowers, which are prepared by cutting the whole or part of the above-ground portion of the plant and placing it in water. There are many types of flowers with unique biological characteristics as part of nature, and various designs are being developed to aesthetically showcase their ornamental value. Additionally, there has been continuous interest in developing ornamental plant materials with distinctive natural beauty, and the demand for diverse cut flower materials is increasing (Park et al., 2007). Therefore, in the field of flowers and floriculture, interest in the development of unique flowers continues to grow.
To appreciate the beauty of plants more closely, various plant materials are used in floral art and flower decoration. Through human creativity and expressive ability, these materials are utilized to design, install, maintain, and manage decorations that enhance both the functionality and aesthetic efficiency of a space.
Most of the floral materials distributed in the flower market are naturalized plants, primarily introduced from foreign countries. Although native plant materials possess high ornamental value, including their leaves and stems as well as their flowers, they have not been widely developed for use as floral art materials in the flower market (Bang, 2010).
Among native plants, the need to use various materials such as cut flowers, cut leaves, cut branches, and fruits, which belong to the cut flower category that accounts for the majority of floricultural materials, for their ornamental value is increasing. However, under Article 27(3)(b) of the World Trade Organization (WTO) Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) (Yoon, 2005), which mandates legal protection of plant varieties, South Korea is required to pay royalties when using foreign plant materials. Therefore the development of garden plants that can be used for floricultural purposes is more urgent (Kim, 2011).
Additionally, with the implementation of international norms regulating the acquisition and use of genetic resources, including the Nagoya Protocol, legal regulations regarding the acquisition and use of these resources are being introduced in each country. Genetic resources, which were once freely used by all countries as a common human heritage, are now recognized as a public good under exclusive ownership (Lee et al., 2021).
Therefore, this study aims to analyze garden plants with potential for use as floral materials to diversify the plant resources currently reliant on imports. The research seeks to classify plants suitable for use as cut flowers by their morphological characteristics and evaluate their applicability for floral utilization.
Research Methods
Literature review on garden trees
To identify garden trees that can be used or potentially utilized as cut flowers, the following references were consulted: Korean Garden and Landscape Tree Field Guide (Jegal et al., 2019), Fruits and Branches More Beautiful than Flowers (Kim et al., 2019), Leaves More Beautiful than Flowers (Kwon et al., 2016), A Quick Guide to Korean Trees 1 and 2 (Park, 2021), and A Quick Guide to Korean Trees 3 and 4 (Park, 2023). Additionally, online plants resources were utilized. The criteria for selecting literature sources were based on the Korean Plant Names Index Committee and the National Institute of Biological Resources. The most commonly used garden plants were investigated. The references were selected from plant field guides that provide detailed descriptions of garden plants, including their stems, branches, leaves, flowers, and accompanying photographs. Based on the researcher's expertise, a total of 367 plant species with high ornamental value across various material categories were classified.
The 367 garden plants identified through the literature review were categorized using the Engler plant classification system. These species were further classified into four groups based on their ornamental components: flowers, leaves, fruits, and branches.
Analysis of current cut flower utilization
To investigate the cut flowers currently distributed and used in the domestic floral market, four floral guides were analyzed: New Floriculture (Kim et al., 2014), Floristry (Seo et al., 2005), Flower Guide (Korean Society of Floral Art and Design, 2017), and Flower Guide (Monceau, 2021). Additionally, online data from the Rural Development Administration, Korea Agro-Fisheries and Food Trade Corporation, and the Floral Distribution Information System were referenced for analysis over a one-year period from October 2022 to September 2023.
Method for selecting garden trees suitable for use as cut flowers
Among the garden trees identified through the first literature review, a secondary comparison was conducted using the list of cut flower items obtained from the second investigation to reclassify the currently distributed and utilized garden trees. Garden trees that are not currently used as cut flowers were further analyzed to identify those with potential for use as cut flowers (Fig. 1).
Systematic framework for selecting usable garden plants.
To establish criteria for selecting suitable garden tree species for use as cut flowers, in-depth interviews (FGI) and surveys were conducted with a total of eight experts: one horticultural gardener, three horticultural therapists, two florists, and two plant specialists (Table 1). The suitability of the criteria and the selected garden trees for use as cut flowers was evaluated through a Focus Group Interview (FGI), a research method designed to gather in-depth information from a small group on a specific topic.
Participants in in-depth expert interviews
Survey data were analyzed using SPSS (Version 29.0) statistical software. Reliability tests, including Cronbach's alpha, were performed to evaluate the validity of the criteria for cut flowers and the selected garden trees' potential for utilization. Frequency analysis and percentage calculations were conducted to assess the validity of each criterion and the feasibility of using the trees as cut flowers. Additionally, descriptive statistics, including mean and standard deviation, were used to derive the overall averages for the cut flower criteria and to identify garden trees with high potential for use as cut flowers.
In this study, in order to find plants that can be used among garden tree species, the KJ method (Kawakita Jiro's idea method) used for creative problem-solving and idea generation, as well as for systematically organizing complex information or ideas to gain insights was used based on the results of statistical processing through a questionnaire. From October 9 to October 15, 2023, in-depth interviews and surveys with experts were conducted to collect opinions on the criteria for cut flowers, and then cut flower criteria were derived based on the collected data. Furthermore, the validity of the garden tree species identified through the literature review as suitable for cut flowers was re-evaluated using descriptive statistics in accordance with the established criteria.
Results and Discussion
Analysis of the current status of garden trees
A total of 367 species were identified and categorized by growth form and family: 177 tree species, 7 species of deciduous broad-leaved shrubs or small trees, 167 shrubs, 13 vine-like shrubs, and 1 species each of semi-evergreen or deciduous shrubs, evergreen broad-leaved vine plants, and semi-evergreen broad-leaved foliage plants.
The Rosaceae had the highest number of species with 57, followed by the Oleaceae with 27 species. The Pinaceae and Caprifoliaceae each had 16 species, ranking third. The Fabaceaecame fourth with 15 species, the Betulaceae fifth with 14 species, the Aceraceae sixth with 12 species, and the Cupressaceae seventh with 11 species. The Ericaceae included 10 species, followed by the Cornaceae and Saxifragaceae with 9 species each. The Magnoliaceae, Aquifoliaceae, Rhamnaceae, Theaceae, and Araliaceae each had 7 species. The Fagaceae, Ulmaceae, Berberidaceae, and Celastraceae followed with 6 species each.
The Taxodiaceae, Moraceae, Nyssaceae, Rutaceae, and Apocynaceae each had 5 species, while the Lauraceae, Nyssaceae, Thymelaeaceae, Rubiaceae, and Verbenaceae each had 4 species. The Salicaceae, Rutaceae, Myrsinoideae, and Bignoniaceae each included 3 species. Families with 2 species each were Taxaceae, Juglandaceae, Elaeagnaceae, Sapindaceae, Meliaceae, Simaroubaceae, Hippocastanaceae, Euphorbiaceae, Buxaceae, Trochodendraceae, Ebenaceae, and Scrophulariaceae. Families with only 1 species each were Cycadaceae, Ginkgoaceae, Castaneaceae, Calycanthaceae, Lardizabalaceae, Ranunculaceae, Tofieldiaceae, Paeoniaceae, Cercidiphyllaceae, Trochodendraceae, Pittosporaceae, Fagaceae, Nyssaceae, Anacardiaceae, Solanaceae, Vitaceae, Malvaceae, Tiliaceae, Sterculiaceae, Flacourtiaceae, Tamaricaceae, Lythraceae, Punicaceae, Styracaceae, Rhamnaceae, Loganiaceae, Adoxaceae, and Illiciaceae (Table 2).
Garden trees selected from literature
Analysis of the current status of cut flowers
Usage status of cut flowers
An analysis of cut flowers listed for auction on the Flower Distribution Information System revealed a total of 341 species out of 637 materials. These included 92 unidentified cut flowers, 55 cut branches, 78 fruits, 3 flower stems, 101 foliage materials, and 12 herbs. Among these, a total of 56 woody plant species were identified as cut flowers: 1 species from Cycadaceae, 3 species from Cupressaceae, 1 species from Salicaceae, 1 species from Betulaceae, 11 species from Rosaceae, 4 species from Saxifragaceae, 1 species from Rutaceae, 2 species from Celastraceae, 1 species from Vitaceae, 2 species from Malvaceae, 1 species from Nyssaceae, 2 species from Thymelaeaceae, 1 species from Cornaceae, 1 species from Ericaceae, 1 species from Theaceae, 6 species from Oleaceae, 3 species from Araliaceae, 1 species from Aquifoliaceae, 1 species from Berberidaceae, 2 species from Caprifoliaceae, 1 species from Pittosporaceae, 2 species from Ranunculaceae, 1 species from Magnoliaceae, 2 species from Verbenaceae, 1 species from Apocynaceae, and 1 species from Anacardiaceae (Table 2).
Among these, 11 species, including Cupressus macrocarpa, Stephanandra incisa (Thunb.), Sorbaria sorbifolia (L.) A.Braun var. stellipila Maxim., Ribes mandshuricum (Maxim.) Kom., Fortunella japonica var. margarita (Swingle) Makino, Gossypium hirsutum Lam., Ligustrum japonicum Thunb., Heptacodium miconioides Rehder, Aquilegia buergeriana Siebold and Zucc. var. oxysepala (Trautv. and C.A.Mey.) Kitam., Callistemon speciosus (Sims) Sweet and Caryopteris incana (Thunb. ex Houtt.) Miq. were found to be distributed as cut flowers but were not included in the 367 species analyzed in the field guide. Additionally, 45 woody plant species from the 367 species analyzed in the guide were identified as currently distributed.
Classification of cut flower plants by type
Among the 56 species of cut flower plants distributed in the floral market, all were used as cut foliage and cut branches. A total of 33 species were used as cut flowers, and 21 species were used for their fruits. Additionally, 11 species were used across all four categories: cut flowers, cut foliage, cut branches, and fruits (Table 3).
Classification of distributed cut flowers
Utilization frequency of cut flowers by type
Cut flowers are utilized in various forms, including flowers, leaves, branches, and fruits, and garden tree species with potential as cut flowers were identified. A total of 45 cut flower species investigated through flower distribution websites and 70 candidate garden tree species were excluded, leaving 252 species analyzed based on previous research and expert opinions for their utilization frequency by type. The utilization potential of the 70 garden plant species was further validated and analyzed by eight experts (Fig. 2).
Selection process for potential cut flower plants among garden tree species.
Selection of garden trees usable as cut flowers
Out of the 367 garden plant species, a total of 70 species were found to be not currently distributed (Table 4). The selection of garden tree species usable in various forms was conducted through in-depth expert interviews and surveys. From the 70 selected garden tree species (Table 4), an evaluation was conducted to determine which plants could be used as cut flowers in the categories of flowers, leaves, branches, and fruits. The first step was to assess the validity of expert criteria for cut flowers. The results are presented in Table 5.
Selection of usable cut flower plants among garden trees
Validity of cut flower criteria
The shape, color, and petal drop progression speed of flowers were identified as critical factors for evaluating cut flower suitability. For leaves, the degree of damage, retention of their original color, and leaf drop progression speed were key criteria. Regarding fruits, shape, color, fruit drop progression speed, and size were ranked as the most significant factors. Among external factors, the durability of cut flowers before and after shipping was deemed the most important determinant. This was followed by preservation ability, ease of storage, and distribution viability, which also showed high levels of validity. However, branch-related factors were found to have minimal impact as criteria for selecting usable garden trees as cut flowers, making them the least influential among the physical attributes of flowers, leaves, branches, and fruits (Table 5).
The standard specifications for floricultural products are essential not only for enhancing the efficiency of distribution but also for improving marketability and ensuring fair trade. These standard specifications consist of packaging standards, including transaction units, packaging materials, dimensions, methods, and labeling requirements, as well as grading standards, such as size, color, freshness, vase life, severity of defects, and sorting conditions (NAQS 2024).
However, the current standard specifications for floricultural products lack objective indicators for assessing the internal quality of cut flowers, such as their weight or stem thickness, as the quality evaluation criteria are composed of items that can be evaluated based on subjective standards. The same applies to the standards for cut flowers. Given the subjective nature of the quality evaluation indicators in the current floricultural product standards, there is a need to introduce metrics for objectively evaluating internal qualities like the weight and stem thickness of cut flowers, as well as to adopt grading manuals for assessing external qualities, such as the degree of blooming and the severity of defects (Park, 2024).
Among the 70 garden tree species, Malus sieboldii and Deutzia gracilis Siebold and Zucc. were identified as plants that could be utilized for all four categories: flowers, leaves, branches, and fruits. Both species were analyzed to have significant potential as ornamental cut flowers. A total of 12 garden tree species—Calycanthus floridus L. var. glaucus (Willd.) Torr. and A.Gray, Mahonia japonica (Thunb.) DC., Berberis thunbergii DC., Prunus triloba Lindl. var. truncata Kom., Prunus glandulosa, Prunus glandulosa, Cotoneaster wilsonii Nakai, Amelanchier asiatica (Siebold and Zucc.) Endl. ex Walp., Pourthiaea villosa (Thunb.) Decne., Deutzia uniflora Shirai, Cleyera japonica Thunb., and Diospyros lotus L.—were found to be usable as cut flowers in three different forms.
A total of 19 garden tree species were identified as suitable for use as cut flowers. These include Cedrus deodara (Roxb. ex D.Don) G.Don, Betula davurica Pall., Betula ermanii Cham., Quercus glauca Thunb., Morus bombycis Koidz., Ficus erecta Thunb., Cinnamomum camphora (L.) J.Presl, Berberis chinensis Poir., Hamamelis japonica Siebold and Zucc., Corylopsis spicata Siebold and Zucc., Liquidambar styraciflua L., Malus baccata, Exochorda serratifolia S.Moore, Malus komarovii (Sarg.) Rehder, Deutzia glabrata Kom., Deutzia crenata f. plena Schneid, Berchemia floribunda (Wall.) Brongn., Chamaedaphne calyculata (L.) Moench, Symplocos sawafutagi Nagam.
A total of 27 garden tree species were identified as being usable for at least one form of cut flower material, such as flowers, leaves, branches, or fruits. These species include uniperus rigida Siebold and Zucc., Juglans regia L., Carpinus turczaninovii Hance, Carpinus cordata Blume, Carpinus laxiflora (Siebold and Zucc.) Blume, Carpinus tschonoskii Maxim., Corylus sieboldiana Blume, Quercus acuta Thunb, Ulmus pumila L., Elaeagnus multiflora Thunb., Lindera erythrocarpa Makino, Calycanthus chinensis (W.C.Cheng and S.Y.Chang) P.T.Li, Asimina triloba (L.) Dunal, Prunus serotina Ehrh, Ribes fasciculatum Siebold and Zucc. var. chinense Maxim., Zanthoxylum piperitum (L.) DC., Tetradium daniellii (Benn.) T.G.Hartley, Acer triflorum Kom., Acer tegmentosum Maxim., cer ukurunduense Trautv. and C.A.Mey., Picrasma quassioides (D.Don) Benn., lex macropoda Miq., Hovenia dulcis Thunb., Indigofera bungeana Walp., Alangium platanifolium (Siebold and Zucc.) Harms var. trilobum (Miq.) Ohwi, Neolitsea sericea (Blume) Koidz., and Fraxinus sieboldiana var. angustata Blume.
However, a total of 10 plant species—Ulmus americana L., Hemiptelea davidii (Hance) Planch., Senna tora (L.) Roxb., anthoxylum armatum DC., Aesculus hippocastanum L., Mallotus japonicus (L.f.) Müll.Arg., Rhamnella franguloides (Maxim.) Weberb., Idesia polycarpa Maxim., Fraxinus mandshurica Rupr., and Fraxinus sieboldiana Blume —were found to have no potential for use as cut flowers in any form, including flowers, leaves, branches, or fruits (Table 6).
Results of selected usable cut flowers among garden tree species
Excluding 10 species such as Ulmus americana L., Hemiptelea davidii (Hance) Planch., Zanthoxylum armatum DC., and Fraxinus sieboldiana Blume, 60 out of the 70 selected garden tree species were identified as being usable for their flowers, leaves, branches, or fruits.
In Korea, characterized by distinct four seasons and diverse vegetation, the utilization and development of garden plants have grown significantly, adapting to a globalized and rapidly evolving era. This has resulted in professionalized and large-scale developments that have brought about significant changes in appearance. However, the utilization of native plants remains insufficient (Bang, 2010). Among the 60 garden tree species identified as usable for cut flowers, 16 were found to be exotic species, while 44 were native species, including 3 endemic species: Carpinus laxiflora, Cornus officinalis var. coreana, and Daphniphyllum macropodum. Endemic species, particularly those found in specific regions, are protected under the "Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from Their Utilization to the Convention on Biological Diversity" (ABS) (Lee et al., 2021). This protocol grants exclusive rights to resource-holding countries, ensuring that any use of their endemic species by foreign entities leads to the sharing of national benefits.
In 2023, Korea's flower imports amounted to approximately $143 million, a 14% increase from the previous year, marking an all-time high (MAFRA, 2023). This trend reflects the lack of development in domestic plant varieties and insufficient utilization of native species, leading to a continued rise in flower imports. Given the increasing demands of the era, it is critical to discover and develop utilization strategies for domestic native materials, including cut flowers and other plant resources, to address these challenges effectively.
Conclusion
In this study, among the total of 367 garden plant species identified from the literature, 70 species were investigated as garden plants with high potential for use, excluding 297 species that are currently being distributed as cut flowers.
Additionally, specific criteria were established for the selection of garden plants based on their suitability as cut flowers. For flowers, the criteria included flower shape, color, and petal shedding rate; for leaves, the degree of damage, color retention, and leaf shedding rate were assessed. Fruits were evaluated based on shape, size, color, and shedding rate, along with post-harvest longevity, preservation, storage ease, and distribution potential.
Among garden plants, 30 species were found suitable for flowers, 27 for leaves, 9 for branches, and 43 for fruits, with fruits being the most versatile category. Malus sieboldii and Deutzia gracilis Siebold and Zucc. demonstrated the highest potential for all categories. Additionally, 12 species, such as Calycanthus floridus L. var. glaucus (Willd.) Torr. and A.Gray, Mahonia japonica (Thunb.) DC., Berberis thunbergii DC., Prunus triloba Lindl. var. truncata Kom., Prunus glandulosa, Prunus glandulosa, etc., were suitable for three categories. while 19 species were suitable for two, and 27 species for one. A total of 19 species, including Cedrus deodara (Roxb. ex D.Don) G.Don, Betula davurica Pall., Betula ermanii Cham., Quercus glauca Thunb., Morus bombycis Koidz., Ficus erecta Thunb., Cinnamomum camphora (L.) J.Presl, Berberis chinensis Poir., Hamamelis japonica Siebold and Zucc., etc. showed high potential for use in two categories. Additionally, 27 species, such as Uniperus rigida Siebold and Zucc., Juglans regia L., Carpinus turczaninovii Hance, Carpinus cordata Blume, Carpinus laxiflora (Siebold and Zucc.) Blume, Carpinus tschonoskii Maxim., Corylus sieboldiana Blume, and etc. demonstrated high potential for use in one category.
Excluding 10 species, such as Ulmus americana L., Hemiptelea davidii (Hance) Planch., Ulmus americana L., Hemiptelea davidii (Hance) Planch., and Fraxinus mandshurica Rupr., and Fraxinus sieboldiana Blume, 60 out of 70 selected species were found to be usable as cut flowers in some form. This indicates that 85.71% of garden plants can be utilized for cut flower purposes, positively contributing to the discovery of diverse cut flower materials.