Abstracts

Chapman, Douglas. 1980. Alone or in combination plantings, yews complement landscape well. Weeds, Trees & Turf 19(7): 72-83.

Yews, due to their rich regal-green color, are effectively used in mass plantings or as specimen plantings. They are effectively combined with many plants but are aesthetically outstanding when combined with bedding plants, such as red geraniums or salvia. Yews grow well in shade or sunny conditions (watch varietal selections). While being perfectly hardy and able to withstand even the coldest winters, yews seem to be most sensitive to overwatering or poorly drained soils. In England, the yew was a sacred tree, believed to be a symbol of long life and/or immortality. Early Christian churches were built in yew groves. In most English churchyards, one can find the yew — a symbolic link to immortality. There is much controversy about how many species of Taxus exist. Three species somewhat universally accepted; English yew (Taxus baccata), Canadian yew (Taxus canadensis), and Japanese yew (Taxus cuspidata). Once the correct variety is chosen, understanding the insects, diseases, and maintenance requirements makes yew an outstanding addition to the landscape.

Williams, D.J. 1980. How slow-release fertilizers work. Am. Nurseryman 151(6): 90-97.

The number of controlled-release products has increased over the years. The products are distinguished by differences in release characteristics and fall into three classes. The classes are: 1) coated water-soluble materials; 2) inorganic materials of low water solubility; and 3) organic materials of low water solubility that decompose by chemical hydrolysis and/or biological activity. The mechanism for nitrogen release varies in each class and responses differ with medium conditions, such as pH, moisture, and temperature. Physical properties of the fertilizers, such as particle size and coating thickness, also influence the release mechanism. A detailed discussion of each class is given to better understand how the fertilizers in these classes work and to understand how environmental and physical factors affect fertilizer performance.

• © 1981, International Society of Arboriculture. All rights reserved.