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- Author or Editor: Harold Davidson x
- HortScience x
Abstract
When one searches the literature for information pertaining to the nutrition of woody ornamental plants it soon becomes obvious that there has not been too much published in this field. And most of the experimental work on the nutrition of trees has been concerned with varying combinations of nitrogen, phosphorus and potassium. Also, most of the work that is reported was done in the field, either to trees growing in the landscape or in nurseries and as a result most of the studies report a positive response only to the application of nitrogen and little or no response to the application of phosphorus or potassium. A brief review of some of the literature on fertilizer experiments is contained in the works of Wikle (18) and Himeleck (9). Since this symposium is concerned with potassium in horticulture, I will confine most of my remarks to the place that this mineral element has on the growth and development of woody ornamental plants.
Abstract
During the spring and fall of 1966, three thousand one hundred and forty-nine pine trees were planted along the Interstate Highway System in Michigan as part of the highway beautification program. The species included: Pinus nigra (Arnold) Austrian pine; P. resinosa (Aiton) red pine; P. strobus (1.) white pine; and P. sylvestris (L.) Scots pine. Plants ranged in size from two feet for some of the red pine, up to six feet for some of the white pine, but most plants averaged four to five feet in height. Specifications required: “that all plants be nursery grown and shall qualify under the AAN Horticultural Standards for the current American Standards for Nursery Stock, ASA Specification Z 60.1.” All of the plantings were made by landscape contractors, who were the successful bidders for each project.
Abstract
The effect of temperature and humidity conditions on the expression of deicing salt spray injury was investigated using terminal buds and stem sections of Norway maple (Acer platanoides L. cv. Emerald Queen). Loss of viability was associated with sodium chloride treatments and appeared in both high (8.3°C) and low (0°) temperatures. Tissue moisture (%) was significantly lower in low moisture (phosphorous pentoxide) atmospheres and in sodium chloride treatments. Penetration of both Na+ and Cl- ions as evidenced by electron micro-probe analysis occurred throughout stem tissues. Deicing salt spray injury in Norway maple appears to be related to penetration of phytotoxic ions and not directly associated with moisture loss through osmotic stress.
Abstract
Preventing fruit formation may be desirable for several reasons: they may retard tree growth and development, present unpleasant odors, make mowing and maintenance difficult, clog drains, attract undesirable birds and insects, stain cars and patios, or be aesthetically unattractive.
Abstract
The overwintering of evergreens without irrigation in plastic structures was best accomplished in a house oriented in a north-south direction and covered with milky polyethylene. Dehydration of evergreens in a structure covered with clear polyethylene and oriented in an east-west direction was attributed to high vapor pressure gradients that occurred in clear days. Evergreens overwintered in structures covered with clear polyethylene should be inspected periodically and irrigated as necessary to prevent desiccation.
Abstract
In recent years there has been a constant increased demand for ornamental trees, shrubs, flowers, garden equipment, and related supplies. The demand was generated by large increases in suburban populations, increased disposable incomes, and more leisure time. These factors have helped create an estimated 81 million home gardeners caring for over 5 million acres of home lawns and gardens. These facts have caused some researchers and tradesmen to proclaim gardening as America's number one hobby.