Propagation of Ornamental Trees, Shrubs, and Woody Vines
Ornamental trees, shrubs, and woody vines are perennial plants. A few ornamental shrubs and vines are used as annuals and planted in landscapes for one season in hardiness zones where they will not survive winter temperatures. This chapter describespropagation systems that include seed, cuttings, grafting, and micropropagation where appropriate for the listed species. Extensive references are included for more in-depth details of propagation. As a general rule, shrubs and vines are propagated by cuttings, whereas trees are produced by seed or selected cultivars grafted onto seedling rootstocks. There are exceptions, such as tree species that can bepropagated by cuttings or micropropagated. In any commercial propagation system it is important to conduct small trials before propagating on a large scale. The propagation techniques and references listed are to serve as a guide. Propagators must develop their own procedures and chemical treatments that work best for their particular propagation systems. Abelia xgrandiflora. Abelia, Glossy Abelia.Commercially propagated with semi-hardwood cuttings. Can be rooted easily under mist in spring, summer, or fall. Rooting is enhanced by applying talc or quick-dips of 1,000 to 2,000 ppm IBA, or IBA-NAA combinations totaling 1,000 to 2,000 ppm have produced superior results (131). Hardwood cuttings also may be rooted in fall or late winter but less successfully than with semi-hardwood cuttings.Abelia is commercially micropropagated. Abies spp. Fir. Seed. Seed propagation is not difficult, but fresh seed should be used, since most species lose their viability after 1 year in ordinary storage. Embryo dormancy is generally present; fall planting or stratification at about 4°C (40°F) for 1 to 3 months is required for good germination. Bulk presoaking A. procera (noble fir) seed in watershould be avoided because of imbibition damage. It is best to allow seeds to slowly uptake water on moist filter paper and then stratify at 4°C (40°F) for a minimum of 3 weeks (237). Alternatively, seeds can be placed for 5 to 10 days in moist perlite for imbibition, and then cold stratified. Abies seedlings are very susceptible to damping-off. They should be given partial shade during the firstseason, since they are injured by excessive heat and sunlight.
propagation of ornamental trees, shrubs, and woody vines Cuttings. Fir cuttings are considered difficultto-root, but A. fraseri hardwood cuttings—selected from young trees, and basally wounded and treated with IBA—can be rooted in high percentages (210). First order lateralsroot in higher percentages than primary axes (49). Cuttings taken from lateral branches root readily, but tend to become plagiotropic. A quickdip of 5,000 ppm IBA and maintaining a bottom heat of 18 to 24°C (65 to 75°F) is best for rooting hardwood cuttings (49). This species, along with white fir (A. concolor), red fir (A. magnifica), and the California ‘Silver Tip,’ are important Christmas treespecies. Grafting. The side-veneer graft is commonly used. Japanese Momi fir (A. firma) is one of the few firs that will tolerate the heavy clay, wet soil conditions (low soil oxygen), and heat of the southeastern United States. Consequently, researchers at North Carolina State University recommend grafting desirable fir cultivars on A. firma rootstock, rather than the less tolerant A. fraseri orA. balsamea (114). Fraser fir (A. fraseri) is cleft grafted onto rootstocks of Turkish fir (A. bornmuelleriana) to reduce losses by phytophthora root rot. Cleft grafting is successful in North Carolina during early sprint (April) when scions are dormant and rootstocks are becoming active (206). Micropropagation. Abies spp. have been regenerated via somatic embryogenesis (228). Abutilon spp....