Japanese silver grass (Miscanthus sinensis) and 14 cultivars were transplanted in northern and southern Florida and evaluated for landscape performance, flowering, growth, and seed viability. All plants survived the 84-week study at both locations with the exception of `Morning Light', where 22% to 33% of the plants died. In northern and southern Florida, `Arabesque', `Adagio', `Cosmopolitan', and `Gracillimus' received the highest visual quality ratings on average throughout the entire study, yet other cultivars such as `Central Park' and `Silberfeder' performed well but had much narrower windows of peak performance. Cultivars such as `Little Kitten' and `Sarabande' performed far better in southern Florida than in northern Florida. Regardless of location, `Morning Light' and `Puenktchen' generally did not perform as well as other cultivars. In northern Florida, four consecutive months of very good to excellent flowering (75% to 100% canopy coverage) were observed for `Adagio', `Arabesque', `Cosmopolitan', `Gracillimus', `Little Kitten', `Sarabande', `Silberfeder', and `Zebrinus'. However, in southern Florida, peak flowering periods for these cultivars were delayed and generally only lasted for 1 to 2 months. On average, plants in northern Florida were larger and produced 2.8 times more flowers than plants in southern Florida. All cultivars produced viable seed with germination of viable seed ranging from 53.6% (`Cabaret') to 100% (`Gracillimus') in southern Florida, and from 49.8% (`Arabesque') to 100% (`Adagio', `Little Kitten', `Sarabande', and `Variegatus') in northern Florida.
Sandra B. Wilson and Gary W. Knox
Sandra B. Wilson and Gary W. Knox
Plant growth, visual quality, flowering, and seed production were assessed for 10 fountain grass (Pennisetum) cultivars planted in northern and southern Florida. All fountain grass cultivars except Rubrum Dwarf fountain grass (Pennisetum setaceum) and Red Buttons fountain grass (Pennisetum messiacum) achieved flower ratings of 3 to 5 in both locations during the first growing season. During the second growing season, chinese fountain grass (Pennisetum alopecuroides), ‘Cassian’ chinese fountain grass (P. alopecuroides), ‘Hameln’ chinese fountain grass (P. alopecuroides), and ‘Red Buttons’ fountain grass flowered better in northern Florida, and green fountain grass (P. setaceum) and ‘Rubrum Dwarf’ fountain grass flowered better in southern Florida. Visual quality of chinese fountain grass and its cultivars generally declined in October without resuming growth through May. ‘Little Bunny’ chinese fountain grass (P. alopecuroides) and oriental pennisetum (Pennisetum orientale) declined dramatically during the first season and did not survive the 84-week study in northern or southern Florida. ‘Rubrum’ fountain grass (P. setaceum) and ‘Rubrum Dwarf’ fountain grass did not produce any seeds.
Sydney Park Brown and Gary W. Knox
A random sample was made from 2000 Extension customers who had attended programs on Environmental Landscape Management within 17 counties in Florida. Four-hundred Master Gardeners and 500 other citizens were sent a questionnaire that gathered information on demographics as well as six landscape practices. Incentives and barriers to practice adoption were also examined. The return rate of the questionnaires was 83%. Results of the analysis and their implication for Extension programming will be presented.
Gary W. Knox and Glenn D. Israel
Environmental Landscape Management (ELM), an extension education program, approaches every landscape as a “system” in which cultural practices interact with each other and the environment. ELM guidelines integrate site conditions, landscape design, plant selection, cultural factors, and recycling in a comprehensive, environment-friendly strategy for managing a landscape. Use of ELM practices by Floridians will conserve resources and protect the environment. The ELM program was evaluated from 1992 to 1994 in 10 counties to measure the program's impact on participants' landscape practices and to provide information on ways to improve program delivery and effectiveness. The evaluation was accomplished by comparing pre-program information on the use of ELM practices with that of a follow-up conducted six months after the program. Responses of this Program Group (n = 473) were compared to those of a Comparison Group of randomly selected Floridians (n = 186). ELM training increased the Program Group's adoption of most practices pertaining to pest management, irrigation, and mowing and pruning. ELM training increased adoption of some fertilization practices and a few recycling and wildlife practices. Energy conserving practices were not widely used by respondents. Respondents maintaining their own yards or those without a permanent irrigation system were more likely to adopt a wide range of ELM practices. The Program Group generally had higher initial levels of adoption of ELM practices than the Comparison Group.
Gary W. Knox, Edward F. Gilman, and Sydney Park Brown
Environmental Landscape Management (ELM) is an extension education program developed to promote resource conservation and environmental protection through appropriate landscape design and maintenance practices. Use of ELM practices by Florida home owners and landscape professionals will conserve energy and water, recycle yard wastes, and reduce inputs of fertilizers and pesticides. Site analysis and appropriate landscape design and plant selection are inherent components of ELM. Guidelines for ELM integrate irrigation, fertilization, pest control, recycling of yard wastes and other cultural practices to result in a holistic approach to landscape management.
Five videos, 3 slide sets, 20 newspaper releases, and a 45-page booklet, The Florida Environmental Landscape Guide, have been produced to support ELM. This information also will be available on CD-ROM in each county extension office.
Rosanna Freyre, Adam Moseley, Sandra B. Wilson, and Gary W. Knox
Mexican petunia (Ruellia simplex Wright) is a non-native plant that was introduced to Florida sometime in the 1940s and since then has naturalized in most of the state and in other southern states. Since 2007, we have developed at the University of Florida/Institute for Food and Agricultural Science in Gainesville the first Ruellia L. breeding program aiming to develop fruitless plants with different flower colors and growth habits that will not be invasive by seed dispersal. A combination of polyploidization and hybridization methods was used. In 2011, a total of 15 plants were selected and grown in southeastern, north–central, and northwestern Florida (Fort Pierce, Citra, and Quincy) using a randomized block design with three blocks and three plants per plot at each site. Plants were evaluated monthly for landscape performance, flowering, and fruiting. Two hybrids (R10-102 and R10-108) had outstanding potential as new fruitless cultivars for the plant industry having improved landscape performance and flowering.
Mack Thetford, Gary W. Knox, and Edwin R. Duke
Full sun trial gardens were established at two sites in northern Florida. Six U.S. native and three non-native warm season grass species were evaluated in a split-plot design. Only eastern gamagrass (Tripsacum dactyloides), elliott's lovegrass (Eragrostis elliottii), gulf hairawn muhly (Muhlenbergia capillaris), little bluestem (Schizachyrium scoparium), and ‘Central Park' maiden grass (Miscanthus sinensis) showed a significant response to supplemental irrigation or fertilization. Supplemental irrigation did not influence foliage height for any of the grasses, whereas supplemental fertilization influenced foliage height only for chinese fountain grass (Pennisetum alopecuroides). The response differences between locations were attributed in part to soil types. This study observed minimal or no response of shoot growth to supplemental irrigation or fertilization for the grass species tested, thereby affirming the broad adaptability and minimal need for inputs for these ornamental landscape plants.
Jyotsna Sharma, Gary W. Knox, and Maria Lucia Ishida
Certain cultivars of magnolia are desirable in landscapes for their uncommon yellow flowers. While cultivars derived from Magnolia acuminata L. (cucumbertree magnolia) are difficult to propagate by stem cuttings, some with mixed parentage appear easier to propagate in this manner. We propagated six yellow-flowered cultivars vegetatively by applying 0, 8, 16, or 30 g·kg–1 (0, 8,000, 16,000, or 30,000 ppm) indole-3-butyric acid (IBA) in talc to bases of terminal stem cuttings collected 5, 7, 9, or 11 weeks after budbreak. Mean rooting percentage over all cultivars increased from 12% (in the absence of IBA) to 34% (after application of 30 g·kg–1 IBA). Rooting percentage and basal stem diameter of a cutting did not seem related. For each collection date, more cuttings of `Ivory Chalice' and `Yellow Lantern' developed roots than the other cultivars. More roots (mean = 5) developed on cuttings of `Yellow Lantern' collected 5 weeks after budbreak or when treated with 30 g·kg–1 IBA than the other cultivars. `Butterflies' largely remained unresponsive, whereas rooting of `Golden Sun,' `Hot Flash,' and `Maxine Merrill' collected 5 weeks after budbreak was 31%, 22%, and 28%, respectively. When data were analyzed separately for selected cultivars, 63% rooting was observed among cuttings of `Ivory Chalice' collected 7 weeks after budbreak. Rooting percentage was higher (22%) among cuttings of `Hot Flash' collected 5 or 7 weeks after budbreak in comparison to later collection dates, but harvest date did not influence rooting of `Yellow Lantern,' which ranged from 44% to 59%. Collection of stem cuttings early in the growing season (5 weeks after budbreak) was beneficial (31% rooting) for inducing rooting among cuttings of `Golden Sun.' We conclude that `Ivory Chalice' and `Yellow Lantern' are promising choices for growers interested in clonal propagation of yellow-flowered cultivars of magnolia. To maximize rooting among these cultivars, terminal cuttings should be collected within 5 to 11 weeks after budbreak and treated with 16 or 30 g·kg–1 IBA in talc. Early collection dates (5 to 7 weeks after budbreak) improved rooting among cuttings of other cultivars but these, particularly `Butterflies,' remain variably recalcitrant and merit further study.
Mathews L. Paret, Aaron J. Palmateer, and Gary W. Knox
Bacterial leaf spot on roses caused by a Xanthomonas sp. is a new disease affecting commercial rose production with the potential to cause major economic losses. In the past few decades, antimicrobial photocatalyst technology has emerged from basic research and development to provide convenient formulations of titanium dioxide (TiO2) nanoparticles, which have the ability to destroy bacteria on surfaces in the presence of light. In this study, a TiO2 nanoparticle formulation containing zinc (TiO2/Zn) was tested for management of bacterial leaf spot on Rosa ‘Noare’. TiO2/Zn caused significant reduction in the survival of Xanthomonas sp. strain Xr-1 on glass coverslips coated with the nanoparticles on exposure to light at 3 × 104 lux for 10 minutes. There was no reduction of bacterial viability in non-coated or non-illuminated controls. Field applications of TiO2/Zn at ≈500 to 800 ppm on Rosa ‘Noare’ significantly reduced bacterial spot severity compared with the untreated control. TiO2/Zn activity was better or on par with the ornamental industry standard for management of rose diseases.