Eight species of container-grown woody landscape plants received a single foliar spray of 0, 25, 50, 100, or 200 mg a.i. ASC-66952 ·liter-1 on 13 June 1990. (ASC-66952 is a proprietary chemical being developed by ISK-Biotech.) Axillary, rhizomatous, and total shoot numbers of `Harbour Dwarf' nandina were increased with increasing concentrations of ASC-66952. Relative to those of the control plants, axillary shoot numbers were increased from 350% with 25 mg·liter-1 to 950% with 200 mg·liter-1, while rhizomatous shoot numbers were increased 144% with the lowest concentration and 477% with the highest concentration. Growth indices were decreased from 2.1% with 25 mg·liter-1 to 9.7% with 200 mg·liter-1. Branching and growth indices of other species tested were minimally affected by ASC-66952 application.
Breeding, selection and evaluation of woody landscape plants has been an active project at the Univ. of Minnesota for many years. The goal of the project is to develop and or identify superior plants that are well adapted to the climatic conditions of Minnesota and other northern areas. About 20 cultivars of many species have been introduced to the nursery trade through this program in the past 20 years. These introductions result from selections made from populations arising from controlled crosses and from open-pollinated populations and native plant populations. One of the primary efforts has been development of the cold hardy, “lights series” of deciduous azaleas. These possess flower bud hardiness of from –35 to –40 °C. Other current breeding activities include efforts with Viburnum, Acer rubrum, Rosa, and intergeneric hybridization in the Pomoidaea subfamily of Rosaceae. An integral part of the project is development and use of techniques to screen for tolerances to various environmental stresses. Approaches used will be discussed and plants currently under evaluation will be described and illustrated with slides.
W. Jack Rowe II, Daniel A. Potter and Robert E. McNiel
Twenty-six purple- or green-leaved cultivars representing 12 species of woody landscape plants were evaluated in the field for defoliation by Japanese beetles (Popillia japonica Newman) over three growing seasons. We further evaluated the hypothesis that, within closely-related plants, purple cultivars generally are preferred over green ones by comparing beetles' consumption of foliage in laboratory choice tests and their orientation to painted silk tree models baited with Japanese beetle lures. Cultivars of Prunus cerasifera Ehrh. and hybrids of that species [e.g., Prunus ×cistena (Hansen) Koehne, Prunus ×blireiana André] were more heavily damaged than nearly all other plants tested. Among maples, Acer palmatum Thunb. `Bloodgood' and A. platanoides L. `Deborah' and `Fairview' were especially susceptible. None of the cultivars of Berberis thunbergii DC, Cercis canadensis L., Cotinus coggygria Scop., or Fagus sylvatica L. were heavily damaged, regardless of foliage color. In the choice tests, purple Norway maples were preferred over green ones in three of four comparisons, but preference varied within the other plant genera. In fact, more beetles oriented to green-leaved tree models than to purple ones. Our results indicate that within a genus, purple-leaved plants do not necessarily sustain more damage than green-leaved ones. Widespread use of certain purple-leaved cultivars of generally susceptible plant species probably contributes to the perception that purpleleaved plants, overall, are preferred. Purple-leaved cultivars of redbud, European beech, smoketree, and barberry, or the purple-leaved Prunus virginiana L. `Canada Red' or Malus ×hybrida Lemoine `Jomarie' may be suitable substitutes for more susceptible purple-leaved plants in landscapes where Japanese beetles are a concern.
Christopher Lindsey, Gate Kline and Mark Zampardo
An interactive computer-based system was designed to improve student plant identification skills and knowledge of ornamental, cultural, and usage information in a woody landscape plant materials course. The program is written for use under ToolBook, a Microsoft Windows based program, and incorporates 256-color high-resolution images and text into a single interactive computer program. Features include: a slideshow that allows students to select which genera and plant characteristics are to be viewed and in what order with the option of an interactive quiz, seeing the names immediately, or after a delay; side by side comparison of any image or text selection; and encyclopedic entries, all with a user-defined path and pace of study.
The system is being used to study how students learn the information presented to them via computer technology and which program features are most useful for improving identification skills and knowledge of other plant features. The computer tracks and logs all activity by students on the system for analysis.
Kathy Zuzek, David Zlesak, Vance Whitaker, Steve McNamara and Stan C. Hokanson
blooming, black spot–resistant landscape rose cultivars available for use in northern continental landscapes ( Zuzek and Hokanson, 2007 ). Below we describe four polyantha rose cultivars developed by the Woody Landscape Plant Breeding and Genetics Project
Karen A. Delahaut and Charles F. Koval
A Nursery Integrated Pest Management program was initiated in Wisconsin in 1991. From 1991 to 1993, the educational and monitoring program enhanced grower familiarity with the IPM concept, as well as provided detailed information on the pest problems common to woody landscape plants in Wisconsin. Educational features of the program include twilight seminars and winter workshops, a pest control guide that described the management strategies available for pests of woody landscape plants, and also statewide pest reporting and pest predictions.
Christopher Lindsey, Gary Kling and Mark Zampardo
UIPLANTS is a program developed under Microsoft Windows to help students in woody plant materials courses. Its many options include an encyclopedic format that displays 256-color high-resolution images of plant identification characteristics and ornamental features coupled with text, side by side image comparisons, “book markers” to return to selected screens, and a slide show that runs a display of images in a user-defined format. The system is being used to study how students learn information presented to them through computers and which program features are most effective in improving plant knowledge. Through computer logging of all student activity within the program and surveys given to the test groups, some basic usage patterns were derived. Students using the program with no incentive tended to use the program in a more comprehensive manner, switching back and forth between the slide show and encyclopedic entries with equal time spent in each. The comparison and “bookmark” features were used but less frequently. Half of the students, given an extra credit incentive based on time, followed this same usage pattern, but the other half simply used the slide show with minimal student–computer interaction.
Peter R. Hicklenton and Kenneth G. Cairns
Nutrient release from Nutricote Type 100 (100-day N release; 16N-4.4P-8.1K), and from a 1:3 mixture of Nutricote Type 40 (40-day N release; 16N-4.4P-8.1K) and Type 100 was affected by time and temperature. The Type 40/100 mixture released nutrients more rapidly over a 5 to 35C range in laboratory studies. Seasonal growth of containerized cotoneaster (Cotoneaster dammeri C.K. Schneid `Coral Beauty') and juniper (Juniperus horizontalis Moench. `Plumosa Compacta') increased with increasing application rates of either Nutricote Type 100 or a 1:3 mixture of Type 40/100 over the range 2-10 kg·m-3. Between 25 June and 27 July, cotoneaster grew more rapidly in media with Type 40/100 Nutricote, but by the end of the season (27 Sept.), fertilizer type showed no effect on plant dry weight. Shoot N was higher in cotoneaster plants grown with Type 40/100 Nutricote than with the Type 100 formulation during the first 2 months of growth, reflecting the more rapid release and uptake of N from the mixture. During the last month the situation was reversed, as nutrients from the Type 40/100 mixture were depleted. Potassium and P shoot concentrations were not affected by fertilizer type. Juniper growth and shoot concentrations of N, K, and P were not affected by fertilizer type at any time during the season. The results provided no evidence that seasonal growth could be enhanced in either cotoneaster (grows rapidly) or juniper (slower growing) by mixing rapid and more slowly releasing types of Nutricote.
Ryan N. Contreras, Jonathan J. Velez and Rob Golembiewski
different study techniques affected student performance in woody landscape plant materials courses. The specific objectives of this study were to determine the relationships among study technique, overall grade point average (GPA), learning style, and