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evaluate saffron crocus as a new specialty crop for New England, to determine whether winter protection was beneficial for saffron crocus production in Rhode Island (USDA zone 6a), and to evaluate corm planting densities for a mesic, high
fruit production and high yields during the second year. Straw mulch or rowcover have been used for winter protection by researchers and growers in the region, who report that winter survival rates vary from poor to excellent, depending on cultivar and
Chopped newspaper at 3.5 and 7.0 kg.m-2 enclosed in white polyethylene sheeting or enclosed in nylon netting at 3.5 kg.m-2 was compared with two layers of 0.64-cm microfoam as winter covering of four taxa of container-grown nursery plants. White polyethylene-enclosed newspaper moderated winter temperatures more than net-enclosed newspaper or two layers of microfoam under white polyethylene. All coverings provided protection against winter injury, as evidenced by container temperature, but net-enclosed newspaper at 3.5 kg.m-2 resulted in a minimal percentage of Daphne burkwoodii `Carol Mackie' plants with three or more shoots longer than 2 cm in the spring. Gaillardia grandiflora, covered by newspaper during winter, had less spring growth than plants covered by microfoam, but all coverings provided protection for Juniperus horizontalis `Prince of Wales' and Physostegia virginiana.
and northeastern United States, cultivars with increased winterhardiness or systems to protect blackberry plants from winter injury are needed. Improved trellis design and cane-training techniques that improve winter-protection strategies, but also
://attra.ncat.org/attra-pub/PDF/garlic.pdf >. Bratsch, T. Morse, R. Shen, Z.X. Benson, B. 2005 No-till organic culture of garlic utilizing different cover crop residues and straw mulch for over-wintering protection, under two seasonal levels of organic nitrogen Virginia Veg. Small Fruit Specialty Crop
likely to survive in that designated zone, but may require additional insulation (winter protection) to prevent extensive cane dieback or death. The necessity to provide winter protection conflicts with consumer demands for low maintenance landscapes
The capacity of plant materials to resume normal growth after exposure to low temperature is the ultimate criterion of cold hardiness. We therefore determined the low-temperature tolerance of five commercially important herbaceous perennial species. Container-grown blanket flower (Gaillardia ×grandiflora Van Houtte. `Goblin'), false dragonhead [Physoste- gia virginiana (L.) Benth. `Summer Snow'], perennial salvia (Salvia ×superba Stapf. `Stratford Blue'), painted daisy (Tanacetum coccineum Willd. `Robinson's Mix'), and creeping veronica (Veronica repens Loisel.) were subjected to 0, -2, 4, -6, -8, -10, -12, -14, -16, and -18C in a programmable freezer. The percentage of survival of most species was adequate when exposed to -10C. Producers of container-grown perennials are advised to provide winter protection measures that prohibit root medium temperatures from falling below -10C.
The globe artichoke (Cynara scolymus L.) is usually propagated vegetatively because plants grown from seed lack uniformity. Furthermore, in much of the United States, only a small percentage of plants grown from seed flower during the first season due to insufficient chilling for vernalization. Artichokes cannot be grown reliably as perennials without winter protection where temperatures are consistently below -10C. The new cultivars Imperial Star (IS) and Talpiot (TP) reportedly produce uniform plants from seed and a high percentage of flower heads (capitulum) the first year with minimal chilling. `Imperial Star' and TP were compared with the standard seed-propagated cultivars `Green Globe Improved' (GG) and `Grande Buerre' (GB). Plants of each cultivar were tested over a 3-year period in Blacksburg, Va., or for 1year in three other locations. Essentially all IS and GG plants flowered after receiving 1356 h of chilling at <10C. With 205 h of chilling, 83% of IS plants flowered compared to 25% for GG. No TP or GB plants flowered after receiving as much as 528 h of chilling. In the mountains of western Virginia, only IS plants established in the field in early May received sufficient chilling to produce flower heads during the late summer and early fall. June transplants did not flower because sufficient chilling was not obtained for vernalization. In warmer areas of central and eastern Virginia, fall establishment for spring harvest may yield a higher percentage of flowering plants compared to spring planting and summer harvest.
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.
The first weed disc (Weed Guard) was introduced to Ontario in the early 1980s. They were made of semirigid plastic similar to 45-rpm records. Small holes allow water to penetrate but weeds germinating on the substrate often grow through them. In the 1990s, we obtained 85% reduction of container weeds using discs made from geotextile fabric (Mori Guard) or foam (similar to polyfoam used for container winter protection). The foam disc tended to curl upward at the edges, become easily windblown, and tended to partially expose the surface of the container mix. During the past 15 years, we have annually reused the same fabric discs (now unavailable due to high unit cost), and have tested various other weed discs, including several new-generation types and also the Mori Weed Bag. The new-generation discs are fabricated from materials such as fabric (Tex-R Geodisc), pressed peat moss (Biodisc), corrugated cardboard (Corrudisc), and plastic (Enviro LID). Both Tex-R Geodisc and Enviro LID were as effective or better in controlling weeds than weekly hand-weeding, herbicides, or the Mori Guard fabric disc. The Mori Weed Bag, a patented black polyethylene sleeve with prepunched holes fitted around the container like a florist's plant prepared for market, is used effectively and almost exclusively by one Ontario nursery. We also tested two types of insulated blanket covers, which when placed around the ball of above-ground container-grown trees, prevented weed growth during the summer and also protected the root ball against cold during the winter. We introduced the garbage bag sleeve, the ultimate no-weed method for pot-in-pot tree culture, which also reduces water use and frequency of irrigation. Due to factors such as under-performance, insufficient demand, and/or high costs, only certain discs are currently manufactured: Weed Guard, Tex-R Geodisc, Biodisc, and Enviro LID. The Mori Weed Bag is available but not the insulated blankets.