Application Status And Cutting Propagation Of Kalmia Latifolia L

Kalmia latifolia L.(Mountain Laurel), a member of Ericaceae, is an evergreen shrub or small tree native to Eastern United States. The plant has light green to dark green leathery foliage, especially showy in winter. The inflorescence consists of a terminal compound corymb and flower colors are usually pink then fade to nearly white. The effort from professional and amateur breeders have yielded many other flower colors, such as pure white, deep pink, red, cinnamon, and burgundy with maroon band inside of corolla. The diversity and attractive flowers make laurel a popular landscape plant and people in state of Connecticut have elected it as their state flower.To better understand the introduction of Kalmia, we had visited its wild populations in Georgia and South Carolina and some nurseries in Northeastern and Southeastern USA. Also, the characteristics of6species in Kalmia and73cultivars of Kalmia lalifolia were described. The results will provide the first hand information for breeders and researchers and guidelines for introducing this beautiful ornamental shrub to China.Cold hardiness is one of the key features for landscape plants. We planted and evaluated26commercial cultivars. The cold hardiness rate and net height growth of104plants were recorded. Since Georgia (USA) and Hunan (China) have similar climate and soil conditions (red clay), we hope to select some cultivars that can perform well in both places. The results concluded that majority of Kalmia latiolia survived in the cold winter (last winter was the coldest winter in Georgia history). Among104plants in the field, most of them performed well during the winter without any damage and only4plants were killed.’Snowdrift’,’Pristine’,’Olympic Fire’,’Tinkerbell’,’Little Linda’,’Minuet’, and ’Elf’ were the most cold-hardy cultivars that were highly recommended for the landscape in Georgia and Hunan. Also, the results provided cold hardiness information for breeding and selecting new cultivars in the future.Because the seed germination rate was low and tissue culture had high production cost, mountain laurel has not been widely used in landscape due to its regeneration difficulty. The rooting of semi-hardwood stem cuttings of Kalmia latifolia was investigated, including impact of pretreatment, temperature during pretreatment period, application methods of hormone, and hormone concentrations on rooting. The results indicated that hormone pretreatment, lower temperature during pretreatment period and higher hormone concentrations did improve the rooting of Kalmia. Further studies should focus on the improvement of Kalmia rooting percentage.In conclusion, Kalmia latifolia is a great ornamental flowering shrub with attractive habits, evergreen foliage, and various flower colors. Georgia should increase its production and landscape uses and Hunan should bring this fantastic ornamental flowering plant to its landscapes.