Due to the Korean Peninsula's long north-south stretch and topographic complexity, there are wide variations in temperature and rainfall. The mean temperature throughout the four seasons ranges from 5oC to 16oC and rainfall from 500 to 1,500 millimeters. Such an environment makes the land a diversified floral region. Lee Woo-tchul's Lineaments Florae Korea (1997) listed 190 families, 1,079 genera, 3,129 species, 8 subspecies, 627 varieties, 1 subvariety and 306 forms of higher plants, including pteridophytes. This means that more than 4,000 kinds of vascular plants, including about 570 endemics currently grow in the country. By comparison, there are about 1,500 species in Denmark and about 2,000 species in Britain. Many plants in northern Korea have elements in common with those growing in Manchuria. While many alpine plants are found in the north and high mountain areas, the central part and the western lowlands have the predominant amount of vegetation, such as broad-leaved deciduous trees. The southern coast and the offshore islands of Jejudo and Ulleungdo are regions where warm-temperate plants grow abundantly. Many evergreen plants growing in the southern parts are identical or similar to those found in the southwestern part of Japan. While there are many plant species in Korea that have common elements with those growing in neighboring countries, the aforementioned environmental conditions have brought about the emergence of many endemic species.

Warm-Temperate Vegetation

Because of the high average annual temperature (14ºC) prevailing over the southern part of the peninsula and the offshore islands- Jejudo, Soheuksando and Ulleungdo- numerous plant species grow in those areas. On the shorelines of Jejudo Island, more than 70 species of broad-leaved evergreens grow. These include Camellia japonica L., Cinnamomun camphora Siebold, Ardisia pusilla DC. Quercus myrsinaefolia Blume, Ligustrum japonicum Thunb., Korthalsella japonica (Thunb.) Engl., Rhaphiolepis umbellata (Thunb.) Makino, Neolistsea sericea (Blume) Koidz., Actinodaphne lancifolia (Siebold et Zucc.) Meisn., Euonymus japonicus Thunb. Euonymus fortunei (Turcz.) Hand. - Mazz., Trachelospermum asiaticum (Siebold et Zucc.) Nakai, Ficus thunbergii Maxim, Machilus japonica Siebold et Zucc., Daphniphyllum tejismanni Zoll., Pittosporum tobira (Thunb.) Aiton, Citrus unshiu Markovich, etc. Also found are such herbal plants as Farfugium japonicum (L.) Kitam., Pollia japonica Thunb., Crinum asiaticum L. var. japonicum Baker, and such broad-leaved deciduous trees as Celtis sinensis Pers, and Elaeagnus macrophylla Thunb.

The southeast slope of Mt. Hallasan on Jejudo is more abundant in warm-temperate vegetation than the northern side. Such vegetation gradually diminishes in number of species as the contour line of temperature moves northward to the southern shore of the peninsula via Geomundo, Soheuksando and other islands. Near Busan and Mokpo, the number of natural broad-leaved evergreens is limited to fewer than 20 species. These areas are also the northernmost limits where Farfugium japonicum (L.) Kitam survive.

Ulleungdo Island, located at 37º 30'N parallels, has many plants of the warm temperate zone, including Daphniphyllum teijsmanni Zoll., Camellia japonica L., Magnolia obovata Thunb., Ilex integra Thunb., Aucuba japonica Thunb., Neolitsea sericea (Blume) Koidz., and Elaeagnus macrophylla Thunb. Camellia japonica L. and Neolitsea sericea (Blume) Koidz. are distributed as far north as Daecheongdo Island, off Hwanghae-do Province. This distribution is caused by seed dispersal through ocean currents.

Temperate Vegetation

The Korean Peninsula, except for the high terrain of Mt. Hallasan on Jejudo Island and the Taebaeksan Range, has a typical temperate zone climate.

It abounds in the type of vegetation natural to the temperate zone, such as Pinus densiflora Siebold et Zucc. and other deciduous broad-leaved trees. Typical deciduous broad-leaved trees found in Korea are: Quercus aliena Blume, Quercus acutissima Carruth., Quercus serrata Thunb., Carpinus laxiflora (Siebold et Zucc.) Blume, Betula platyphylla Sukaczev var. japonica (Miq.) Hara, Carpinus tschonoskii Maxim., Fraxinus rhynchophylla Hance, Salix gracilistyla Miq., Tilia amurensis Rupr., Styrax japonica Siebold et Zucc., Forsythia koreana (Rehder) Nakai, Lespedeza biclor Turcz., Rhododend-ron mucronulatum Turcz., Rhododendron yedoense Maxim. var. poukhanense (Lev.) Nakai, and Rhododendron schlippenbachii Maxim. Herbaceous plants in this zone include Miscanthus sinensis Andersson, Miscanthus sacchariflorus (Maxim.) Benth., Calamagrostis arundinacea (L.) Roth, Chrysanthemum zawadskii Herbich, Hylomecon vernalis Maxim., Primula sieboldii E. Morren, Platycodon grandiflorum (Jacq.) A. DC., Adenophora triphylla (Thunb.) A. DC., Codonopsis lanceolata (Siebold et Zucc.) Trautv., Melanpyrum reseum Maxim., Elsholztia splendens Nakai and Gentiana pseudoaquatica Kusn.

Among the endemic species thriving in Korea are Abeliophyllum distichum Nakai, Hylomecon hylomeconoides Nakai, and Aconitum chiisanense Nakai.

Cold-Temperate Vegetation

Cold temperate plants grow in the northern part of Korea and in the mountains, such as Mt. Seoraksan (1,000 meters), Mt. Jirisan (1,300 meters) and Mt. Hallasan (1,500 meters), where the mean annual temperature on all three mountains is 5oC. Typically inhabiting these locations are such needle-leaved trees as Abies nephrolepis Maxim., Larix olegensis A. Henry var. koreana Nakai, Thuja koraiensis Nakai, Picea jezoensis (Siebold et Zucc.) Carriere, Pinus pumila (Pall.) Regel, Juniperus chinensis L. var. sargentii A. Henry, Picea koraiensis Nakai, Abies Koreana Wilson, Taxus cuspidata Siebold et Zucc. and broad-leaved deciduous trees as Quercus mongolica Fisch., Quercus dentata Thunb., Chosenia bracteosa Nakai, Betula platyphylla Sukaczev var. japonica (Miq.) Hara, Betula ermanii Cham., Betula costata Trautv., Salix myrtilloides L., Vaccinium uliginosum L., and Syringa dilatata Nakai.

As for endemic plants, there is a predominant growth of Echinosophora koreensis Nakai in Hamgyeongbuk-do Province and near Yanggu, Gangwon-do Province. Myeongcheon-gun, in Hamgyeongbuk-do Province, is the native habitat of Sasa coreana Nakai and forms the northern limit for bamboo. The endemic herbaceous plant is Hanabusaya asiatica Nakai, which grows in the northern part of the country. Rheum coreanum Nakai is found on the Bujeon Plateau, on the Jangbaeksan Range, Hamgyeongnam-do Province.

There are many kinds of plants common to Korea and Manchuria. Typical of these include: Astilboides tabularis (Hemsl.) Engl., Acerphyllum rossii (Oliv.) Engl. and Jeffersonia dubia (Maxim.) Benth. & Hook. f. Pinus pumila (Pall.) Regel. These plants grow abundantly in the northern mountains as well as on Mt. Seoraksan. Thuja koraiensis Nakai, which grows in the northern mountains, can be found on the higher part of the Taebaeksan Range. Vaccinium ulginosum L., grows on the summits of Mt. Seoraksan and Mt. Hallasan. This is regarded as a relic species, its present location resulting from the climatic changes which presumably occurred during the Tertiary Period.

Empetrum nigrum L. var. japonicum K. Koch grows in the northernmost regions and the southern end of Mt. Hallasan. Diapensia lapponica L. var. obovata F. Schmidt is found on Mt. Hallasan and in Japan. Their distribution suggest that the Korean Peninsula, Jejudo Island, and the Japanese archipelago may once have been a connected landmass.

Major flora in the cold-temperate climate of the northern forest areas include Larix olgensis A. Henry var. koreana Nakai, Picea jezoensis (Siebold et Zucc.) Carriere, Abies nephrolepis Maxim., Pinus koraiensis Siebold et Zucc., Picea koraiensis Nakai, and Abies holophylla Maxim.

The important needle-leaved trees growing in the Mt. Geumgangsan include Pinus koraiensis Sieb. et Zucc., Abies holiphylla Maxim., Picea jezoensis (Siebold et Zucc.) Carriere, Larix olgensis A. Henry var. koreana Nakai, and Thuja koraiensis Nakai. The predominant species growing on Mt. Jirisan are Juniperus chinensis L. var. sargentii A. Henry, Pinus koraiensis Siebold et Zucc., Abies holophylla Maxim., Abies Koreana E.H. Wilson, and Picea jezoensis (Siebold et Zucc.) Carriere. Near the summit of Mt. Hallasan on Jejudo Island grow Abies Koreana E.H. Wilson and Juniperus chinensis L. var. sargentii A. Henry.

Flowering Periods

July is the season when flowering reaches its peak. Although summer is the peak of the flowering season, there are quite a few species that bloom during the spring and autumn. Woody plants, for example, tend to have their flowering peaks in May.

Spring flowers include: Forsythia koreana Nakai, Rhododendron mucronulatum Turcz., Lonicera praeflorens Batalin, Fraxinus ryhnchophylla Hance, Abeliophyllum distichum Nakai, Prunus ansu Komarov, Prunus yedoensis Matsum., Magnolia kobus DC., Sorbus alnifolia (Siebold et Zucc.) K. Koch, Ginkgo biloba L., Iris rossii Baker, Pulsatilla koreana (Y. Yabe) Nakai, Erythronium japonicum Decne., Berberis amurensis Rupr., Corus officinalis Siebold et Zucc., Hylomecon vernalis Maxim., and Viola mandshurica W. Becker.

Plants blooming in summer comprise: Paeonia japonica (Makino) Miyabe et Takeda, Paeonia lactiflora Pall., Paeonia suffruticosa Andrews, Iris ensata Thunb. var. spontanea (Makino) Nakai, Rosa rugosa Thunb., Sorbus commixta Hedl., Magnolia sieboldii K. Koch, Maianthemum dilatatum (Wood) Nelson et J.F. Macbr., Lilium concolar Salisb., Lilium distichum Nakai, Lilium hansonii Leitchtlin, Morus alba L., Chenopodium album L. var. centrorubrum Makino, Syringa wolfi C. K. Schneid., Dianthus chinensis L., Rosa multiflora Thunb., Hypericum ascyron L., Cirsium japonicum DC. var. ussurinese (Regel) Kitam., Platycodon grandiflorum (Jacq.) A.DC., Phytolacca insularis Nakai, Hanabusaya asiatica Nakai, and Anemone narcissiflora L.

Autumn bloomers include Miscanthus sinensis Anderson, Miscanthus sacchariflorus (Maxim.) Benth., Sedum aizoon L., Gentiana scabra Bunge, Elscholtzia splendens Nakai, Patrinia scabiosaefolia Fisch., Aster incisus Fisch., Chrysanthemum zawadskii Herbich, and Lespedeza bicolar Turcz.

During the winter Camellia japonica L. can be seen blooming on Jejudo, the Heuksando islands, as well as on the southernmost coast.