Crabapples (Malus spp.) are commonly planted ornamental trees in public and private landscapes. Hundreds of selections are available that represent a wide range of growth habits, ornamental traits, and varying degrees of resistance/susceptibility to disease. We distributed 1810 questionnaires in 13 states (Oregon, Washington, Utah, Colorado, Minnesota, Iowa, Missouri, Illinois, Indiana, Michigan, Ohio, New York, and Pennsylvania) to members of either nursery and landscape associations or the Associated Landscape Contractors of America (ACLA, Herndon, Va.) to identify crabapple preferences across a broad geographic region of the United States. We also were interested in learning if regional disease problems were important to green-industry professionals as they decide which crabapples to include in their inventories. Our respondent population numbered 511 (28.2% response rate). A large percentage of respondents (79.4%) said their retail clients focused mostly on fl ower color when choosing crabapples for the home landscape, while commercial clients showed slightly more interest in growth habit (32.5%) than fl ower color (28.7%). `Prairifire' was identified by respondents in all regions, except the west-central (Colorado and Utah), as the crabapple most frequently recommended to clients when tree size is not important. Respondents in the west-central region most often (48.7%) recommend the fruitless selection `Spring Snow'. Respondents in all regions, except the west-central, identified apple scab (Venturia inaequalis) as the most prevalent crabapple disease and named scab-susceptible `Radiant' as the selection most frequently discontinued.
James P. Romer, Jeffery K. Iles, and Cynthia L. Haynes
Tomasz Anisko, Cynthia L. Haynes, and Orville M. Lindstrom
Freeze tests were performed on stem sections of Fraxinus americana, Lagerstroemia indica Magnolia gradiflora, Rhododendron `Red Ruffle', Zelkova serrata, and leaves of Magnolia grandiflora and Rhododendron `Red Ruffle' in the tinter and summer of 1993. Freeze injury was quantified using electrolyte and phenolic leakage techniques and compared to the lethal temperature range determined by visual method assisted by differential thermal analysis. Richards function was fitted to the electrolyte and phenolic leakage data by the modified Gauss-Newton method. The inflection point of the Richards function coincided with the lethal injury range for non-acclimated leaves, but overestimated the freeze tolerance for acclimated leaves and for both acclimated and non-acclimated stems. A proposed interception point of the lower asymptote and a line tangential to the curve inflection point provided an improved estimate of the lethal injury range in most of the species.
Grant L. Thompson, Cynthia L. Haynes, and Samantha A. Lyle
High-resolution scans of plant cuttings were made for a plant identification course to create additional study resources. Stems, flowers, leaves, and other parts with identifiable features were cut and placed on a high-quality flatbed scanner. A framework suspended a black background cloth above the cuttings to create a dark scanning environment, and it was placed far enough away from the scanner glass so as not to appear in the scanned image. Botanical scans can be shared, manipulated, composed, and otherwise provided to students for study materials. Scans are complementary to other common study aids such as pressed herbarium samples or photography.