Production and use of sweet olive (Osmanthus armatus), fragrant tea olive (O. fragrans), holly tea olive (O. heterophyllus), and fortune’s osmanthus (O. xfortunei) as a landscape plant is currently limited to U.S. Department of Agriculture (USDA) Hardiness Zones 7 to 10, and nursery growers wish to extend the range of these species into colder climates. To provide recommendations to growers and landscapers and inform breeding efforts for cold-hardiness improvement, a replicated trial was conducted in a USDA Hardiness Zone 6b/7a transition zone. Fifteen cultivars and two unnamed accessions representing four species were evaluated for growth, stem necrosis, and flowering in a pot-in-pot production system from 2015 to 2017. One-half of the plants in each cultivar were moved to winter protection each November and returned to the field each May. There were significant differences in growth and cold-hardiness among cultivars. Percent increase in the growth index after three growing seasons for winter-exposed accessions of sweet olive, fortune’s osmanthus, fragrant tea olive, and holly tea olive averaged 867%, 1175%, 155%, and 6361%, respectively. Percent stem necrosis in May 2017 for sweet olive, fortune’s osmanthus, fragrant tea olive, and holly tea olive averaged 1.1%, 2.7%, 44.8%, and 20.2%, respectively. The most cold-tolerant accessions based on stem necrosis and growth index of winter-exposed plants were ‘Kaori Hime’, ‘Hariyama’, ‘Shien’, ‘Head-Lee Fastigate’, and ‘Rotundifulius’ holly tea olive, ‘San Jose’ fortune’s osmanthus, and ‘Longwood’ sweet olive. Of these cultivars, Kaori Hime, San Jose, and Longwood flowered under winter-exposed conditions. All fragrant tea olive cultivars were damaged by winter exposure. ‘Fodingzhu’ was the only fragrant tea olive cultivar that flowered each year under winter-exposed conditions. Evaluation and breeding efforts are continuing to extend the range for production and growth of this genus.
or aquatic habitats. The symbols also indicate whether plants require winter protection, are used in window boxes, are medicinal or toxic, are used as cut flowers or fruit decoration, or are otherwise useful. There is even a symbol for fragrance. Even
into areas with more severe winter conditions, cultivars with increased winterhardiness and systems to protect blackberry plants from winter injury are needed. Improved trellis design and cane-training techniques along with enhanced winter protection
, and the necessity for increased precision in irrigation and fertilization practices all increase production costs over field-grown material. Other disadvantages of container growing include the need for winter protection, root mortality from lethal
plants were maintained in an isolated nursery area until they were covered with a polyethylene foam blanket (Hummert International, St. Louis, MO) and plastic sheeting for winter protection. On 20 Apr. 2014, sedge plants were uncovered. One-year-old ‘Bob
, ‘Félix Leclerc’ cultivar can survive in Canadian zone 3A with a small cover of snow or in zone 3B without winter protection. The use of this cultivar may to be marginal in zones 3A to 8B due to tip damage. The cultivar reached its full potential for
climatic zones 3A to 9B during 1999 to 2005 ( McKenney et al., 2001 ; Ouellet and Sherk, 1967 ). ‘Emily Carr’ can survive in Canadian zone 3A with a small cover of snow or in zone 3B without winter protection but is well adapted to zones 5B through 8B
the American origin grape cultivars, and winter protection is required in regions having a cold climate. ‘Sujeong’ vines have relatively high disease resistance to powdery mildew ( Erysiphe cichoracearum DC.) and gray mold ( Botrytis cinerea Per
black plastic provided greater winter protection than a bare-soil production system with straw mulch applied in the spring, and directly led to greater marketable weights and bulb diameters. Two varieties, ‘Idaho Silverskin’ and ‘Persian Star’, were the
previously described. Potted seedlings were grown outdoors under natural conditions with supplemental irrigation for anatomical and budding experiments. On 25 Nov. 2007, potted seedlings were covered with a polyethylene foam blanket for winter protection