‘Frosty Morning’, ‘Patchwork Quilt’, ‘Irish Mist’, and ‘Pistachio Ice Cream’ Ornamental White Clover (Trifolium repens L.)

Abstract

White clover (Trifolium repens L.) is an annual or short-lived perennial found throughout temperate regions of the world (Gibson and Cope, 1985). Originally native to the Mediterranean (Ellison et al., 2006), white clover grows in a wide range of temperatures and in nearly any soil type provided there is enough moisture and sunlight (Gibson and Cope, 1985). In addition, white clover is a frost-tolerant species with little frost damage observed on leaves after exposure to mild frosts (up to –5 C) (Caradus, 1995; McCully et al., 2004). The plant has a prostrate growth habit (Leffel and Gibson, 1973) and spreads along the ground through stolons. White clover is primarily grown as forage for livestock (Van Keuren and Hoveland, 1985), but the plant has also been cultivated for ornamental use. Ornamental cultivar development in the species is possible primarily because of the many attractive leaf marks that are expressed. The attractive foliar marks, combined with its low, spreading growth habit and frost tolerance, makes white clover ideal for development as an ornamental bedding plant. In addition to the attractiveness of white clover developed for ornamental use, there is also folklore associated with the plant that could make it more appealing to ornamental consumers. White clover might have been the ‘‘shamrock’’ plant used by St. Patrick to teach Christianity in Ireland (Kennedy, 1919). White clover also has a long history of being used as a token of good fortune. White clover was believed to ward off evil spirits by the Celts (Taylor, 1985). Nearly 150 years ago, Masters (1869) described girls using fourleaf clovers as ‘‘a token of perfect happiness.’’ In the early 20th century, finding a four-leaf clover was a sign of good luck or a sign that a girl would soon meet her future husband (Beckwith, 1923). To this day, people search for four-leaf clovers to keep as a good luck charm. In 2002, an ornamental white clover breeding program was initiated at The University of Georgia with the goal of developing cultivars with highly ornamental phenotypes and improved persistence in the Southeast. Four white clover cultivars, Frosty Morning (tested as genotype 04-O-2), Patchwork Quilt (tested as genotype 04-O-6), Irish Mist (tested as genotype 04-O-33), and Pistachio Ice Cream (tested as genotype 04-O53), were developed at The University of Georgia. These cultivars have unique phenotypes that are distinct from other commercially available ornamental white clover cultivars. After 2 years of evaluation in the field, the four genotypes were found to be comparable or superior to two commercially available ornamental white clover cultivars, Dragon’s Blood and Dark Dancer, in terms of survival and stand quality in the southern United States (Tables 1–3). Thus, the four released cultivars were approved for release by The University of Georgia’s Ornamentals Release Committee in 2008 for use as ornamental annuals or short-lived perennials (Fig. 1).