Growth of Hibiscus rosasinensis L. `President' under daily irrigation and decreasing irrigation frequency was compared in a 5 pine bark : 4 sedge peat : 1 sand (by volume) medium amended further with 0%, 10%, 20%, or 30% (by volume) Axis, a kiln-fired diatomaceous earth granule. Half of each substrate treatment also was drenched three times with Agroroots, a kelp extract. Shoot and root dry weights were compared after 4.5 months of growth. Container media amended with Axis at 10% volume yielded hibiscus plants with higher shoot dry weights than nonamended media. Root-zone drenches with Agroroots increased shoot dry weights of plants subjected to decreasing irrigation frequency and grown without Axis, but did not significantly affect plants receiving daily irrigation. Shelf-life effects of Axis treatment revealed that all plants reached the permanent wilting point 5 days after cessation of daily irrigation. Both products may allow container plant production with less irrigation. Further tests should be conducted with a broader range of species.
Alan W. Meerow and Timothy K. Broschat
Wagner Vendrame, Kimberly K. Moore and Timothy K. Broschat
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.
Philip Busey, Timothy K. Broschat and Diane L. Johnston
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.
Alan W. Meerow, Timothy K. Broschat and Michael E. Kane
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.
Amy L. Shober, Geoffrey C. Denny and Timothy K. Broschat
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.
Jiaming Yu, Timothy K. Broschat, William G. Latham and Monica L. Elliott
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.