Loropetalum chinense var. rubrum is an evergreen, purple-leafed, medium-size shrub from Hunan Province, China (Hou et al., 2003). It is a member of the witch hazel family (Hamamelidaceae) and is defined as a variety of L. chinense (Creech, 1960). The gracefully layered branches are laden during spring and sporadically throughout the year with pendulous, bright-pink, spiderlike flowers. It is fast growing and tolerant to diseases and insects. Loropetalum chinense var. rubrum is versatile and can be grown in mild coastal climates in light shade to full sun, and can tolerate the more extreme winter and summer temperatures associated with other regions. As an important ornamental plant, L. chinense var. rubrum is very popular in Chinese cities and has been introduced into many foreign countries like America and Japan. For example, two selections of the hot-pink/purple-flowered L. chinense var. rubrum were introduced into the United States from Nihonkaki Nursery, Kawaguchi City, Japan, by the former U.S. National Arboretum Director, John L. Creech, in September 1989 at the request of Sylvester G. March (Gawel et al., 1996). The plants rapidly entered the commercial market. In an attempt to give some order to the confusion of multiple accessions and clones, the U.S. National Arboretum named the purple-foliage form ‘Burgundy’, and the green-foliage form ‘Blush’. More than 15 different introductions of L. chinense var. rubrum have been established in North America since the late 1980s (Hou et al., 2004). Selection and registration of cultivars has been carried out since then.
In recent years, with rapid introduction and commercialization of L. chinense var. rubrum, much confusion concerning the identity of the cultivars has arisen. Although many investigations have been carried out by Chinese researchers (Hou et al., 2003; Huang et al., 2004; Liu and Zhang, 2001; Song et al., 1982; Tang and Zhou, 2001; Tang et al., 2003), the study of L. chinense var. rubrum in China is still in its primary stage, and accessions have not been adequately characterized for morphological traits. The extent of phenotypic diversity among L. chinense var. rubrum accessions throughout the world is not known. Evaluation and comparison of accessions in different seasons will be helpful in developing improved cultivars and in cultivar identification.
The objectives of this study were to 1) compare leaf and flower traits of various accessions in spring, summer and autumn; 2) characterize phenotypic diversity among these accessions using cluster analysis; and 3) select some accessions with good characters to use in the landscape.
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