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- Author or Editor: Timothy K. Broschat x
New guinea impatiens (Impatiens hawkeri) (NGI) `Pure Beauty Rose' (PBR) and `Paradise Orchid' (PO) were grown in full sun, 55% shade, or 73% shade and fertilized with a controlled-release fertilizer (CRF) [Nutricote Total 13-13-13 (13N-5.7P-10.8K), type 100] incorporated at rates of 2, 4, 6, 8, 12, 16, 20, 24, 28 and 32 lb/yard3 of growing media (1.2, 2.4, 3.6, 4.7, 7.1, 9.5, 11.9, 14.2, 16.6, and 19.0 kg·m-3). Plant quality rating, shoot dry weight, and flower number were measured at harvest and substrate samples were collected to analyze final substrate pH and electrical conductivity (EC). For both cultivars, light intensity and fertilization rate interactions were different for shoot dry weight and flower number, but there was no difference in plant quality rating between the light levels. Quality ratings of both PBR and PO plants increased as CRF rate increased to 12 to 16 lb/yard3 above these levels quality was not improved. Shoot dry weight of PBR plants grown in full sun increased as CRF rate increased to 28 lb/yard3 and then decreased, while shoot dry weight of plants grown with 55% and 73% shade increased as CRF rate increased to 20 and 16 lb/yard3, respectively, with no further increases. Shoot dry weight of PO plants grown in full sun and 55% shade increased as CRF rate increased to 28 and 24 lb/yard3, respectively, with no further increases, while shoot dry weight of plants grown with 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased. Flower number of PBR plants grown in full sun, 55% shade, and 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased. Flower number of PO plants grown in full sun increased as CRF rate increased to 28 lb/yard3 and then decreased, while flower number of plants grown in 55% and 73% shade increased as CRF rate increased to 24 lb/yard3 and then decreased.
Phenoxy and related herbicides used in turfgrass have the potential for volatilization and movement from treated areas. Three studies assessed potential injury to subtropical landscape plants caused by volatile turf herbicides in polyethylene enclosures. Phenoxy herbicide mixtures were emphasized. There were significant differences among the seven landscape species tested. The most sensitive species were african marigold (Tagetes erecta), joseph's coat (Alternanthera ficoidea), and tomato (Lycopersicon esculentum). Severe injury was caused by exposure to herbicides containing 2,4-D isooctyl ester and MCPA isooctyl ester. Exposure to individual active ingredients 2,4-D dimethylamine, dicamba acid, atrazine, and metsulfuron resulted in no injury to the species tested.
Rapid population growth and urbanization in Florida have increased the number of urban landscapes that receive fertilization and irrigation. Consequently, maintenance of these landscapes may contribute to water shortages and water quality degradation. This article 1) describes the current fertilizer and water use practices that are used by homeowners and landscape professionals; 2) summarizes the research related to nutrient and water use by landscape plants; and 3) provides an overview of the critical issues that should be considered as we evaluate the need for improved management of water and nutrients in urban landscapes.
An amaryllis breeding program using diploid species not represented in commercial tetraploid cultivars has been underway since 1988. Objectives are to develop evergreen cultivars with attractive foliage and fragrant flowers of novel form and coloration. Five crosses with Hippeastrum papilio as a parent were evaluated at first flowering in the spring of 1990. The F-1's showed significant variation, suggestive of high heterozygosity within the parental genomes. Several natural tetraploids were identified among the progeny. Superior selections were made, and sib- or intercrosses accomplished. We estimate that a minimum of 50% genes from H. papilio will need to be maintained to guarantee evergreen foliage in the progeny. Superior F-1's have also been crossed with fragrant, trumpet-flowered primary hybrids, and new primary F-1's are being generated with H. papilio and these species or their hybrids, as well as with H. reticulatum var. striatifolium. A percentage of these germinated seedlings have been treated with colchicine to induce polyploidy. The best F-1 selections are also being micropropagated, and induction of polyploidy will be attempted in a percentage of the subcultures.
Sun-grown (2100 μmol·s-1·m-2) Ptychosperma elegans palms were acclimatized for 0, 1, 2, 3, 4, 6, 8, or 12 months under shade (570 μmol·s-1·m-2). Plant height was greater in palms grown under shade for 6 months or longer and plant color gradually improved when palms were grown under shade for 2 months or longer. Leaves produced under shade had an undifferentiated mesophyll comprised of isodiametric and rectangular cells. Full sun leaves had a mesophyll with distinct palisade cells and abaxial mesophyll cells comprised of rectangular and isodiametric cells. The mesophyll in both light levels had small intercellular spaces. Sun leaves were replaced under shade at a rate of about one leaf every 3 months. After 10 weeks in an interior environment, the number of green leaves remaining on the palms was directly proportional to the number of shade leaves on the plant before placement in the interior environment and to the length of time the palms had been grown under shade.
Fifty-two cultivars of cannas (Canna X generalis L.H. Bailey and C. indica L.) were evaluated in a field planting for relative susceptibility to Hippeastrum mosaic (HM), a disease caused by Hippeastrum mosaic virus. The cultivars ‘Mrs. Pierre S. DuPont’ and ‘Pink Gem’ were the most susceptible to HM, while 2 red-leaved cultivars, ‘Wyoming’ and ‘Ambassador’, were highly resistant. Thirty-eight cultivars of cannas grown in containers were evaluated for susceptibility to canna rust (Puccinia thaliae Dietel). The cultivars ‘Halloween’ and ‘Yellow King Humbert’ were highly susceptible to rust, while the most resistant cultivars, ‘Louis Cayeaux’ and ‘La Boheme’, were still moderately susceptible. No single cultivar exhibited good resistance to both HM and rust.
The genus Heliconia (Heliconiaceae) includes a number of species showing potential as commercial cut flower crops (1). H. Psittacorum and some of its hybrids (e.g., ‘Golden Torch’) are particularly promising because of their attractive flowers, long straight clean peduncles, prolific year round flower production, excellent postharvest characteristics, and few pest problems. The inflorescences can be used in a manner similar to those of bird-of-paradise (Strelitzia reginae), but they are less massive and are therefore, easily incorporated into smaller floral arrangements.
Palms are an important component of landscapes in tropical, subtropical, and Mediterranean climates, but are anatomically very different from broadleaf trees. Very little is known about the movement and persistence of systemic fungicides into various parts of the palm canopy. This information is critical in selecting fungicides that may be effective against diseases that infect specific parts of the palm. In this study, potassium phosphite was injected into mature coconut palms (Cocos nucifera) at rates of 0, 30, 60, or 90 mL per tree. Various leaf tissue samples were collected periodically thereafter up through 60 weeks and were analyzed for phosphite concentrations. Phosphite moved quickly into leaflet tissue, but concentrations dropped off sharply between 1 and 5 weeks after injection. This drop in leaflet concentrations was balanced by a concomitant increase in spear leaf concentrations. Phosphite persisted at high concentrations in basal rachis tissue of both old and new leaves throughout the experiment. This suggests that this material may be useful for controlling diseases that infect spear leaves and petiole or rachis tissue, but not leaflets.