Scientific Research Journal Update

By Susan Switras and Jeff Gillman

Recently, a study was done at the University of Nebraska to determine how midwestern homeowners feel about the relationship between quality-of-life and landscape design. The findings showed conclusively that homeowners experience an enhanced quality-of-life with aesthetically pleasing and functional landscapes. The participants in this study made several comments on what they expected from nursery and landscape professionals. They felt nurseries should be professional, knowledgeable and flexible, as well as have trained staff working during all hours the nursery was open for business. They expect landscape designers to be knowledge of functional issues, to have insights into the long term effects of a landscape, to be respectful of individuality, and to have a willingness to get to know the client. They cited the main reason for unsatisfactory experiences with a landscape designer as being a lack of communication between the design professional and the customer, as well as the feeling that the customer was not being given adequate time. Quality customer service and strong communication skills are a must in this industry as far as the customers are concerned. To read more about the findings of this study, see the March 1999 issue of the Journal of Environmental Horticulture.

Other research in the past few months has focused on moisture tension and growth, substitutes for peat in growth media, pesticide and herbicide runoff, and growth retardants effects on flowering. As we write these reports, we once again ask you to remember that we are reporting other peoples research and neither endorse nor refute their method or results. We recommend that you look these articles up if you have any questions on the research we are summarizing. A full citation of each paper is included at the end of the article. In a few of these articles, the use of a particular compound is may be inconsistent with the label recommendations. We strongly discourage the use of these compounds in any way that does not agree the manufacturers label.

• Canadian sphagnum peat and Philippine coconut coir dust were compared as media mix components in growing Madagascar dragon tree (Dracaena marginata Lam.) and peace lily (Spathiphyllum Schott Petite). There is concern about the continued harvesting of Sphagnum peat, because it is a part of a wetland ecosystem. This study, carried out at the University of Florida, tested several different mixes with each component for both species. Coconut coir dust used in place of peat did not significantly affect the growth of the above species in the mixes studied.

• Kevin R. Keel et al. at Auburn University monitored the release and subsequent leaching of oxadiazon from herbicide-coated control-released fertilizers. Of the five fertilizers tested (Meister, Nursery Special, Polyon, Osmocote and Nutricote), Polyon was found to release less herbicide in the first few leaching events than the others, thus releasing its herbicide coating at a more constant rate over the eleven leachings. When the same fertilizers were coated with isoxaben (another herbicide), results were the similar. Another experiment was performed to determine if applying an oil or a sticker to oxadiazon-coated Osmocote would result in a more uniform release of oxadiazon. Complex or Intac stickers or Prime OiI resulted in a more consistent rate of leaching.

• Methods to reduce the amount of pesticide runoff from container nurseries were studied at Clemson University. Three different pesticides were applied to container nursery beds, and the runoff measured. Cyclic irrigation reduced water runoff volume by 15% in comparison to continuous irrigation. The combination of cyclic irrigation and grass waterways reduced the concentration of isoxaben in the runoff both on the day of application and throughout the study.

• In another study on nursery runoff, sub-surface flow and free-surface flow wetland cells were used to treat collected runoff in a capture and recycle system at Texas A&M University. They studied the growth of the wetland plants used to treat the runoff, and the recovery of these plants from winter injury. A single pass of runoff did not raise the salinity of the water (for reapplication), but did effectively reduce the nutrient runoff concentrations. In addition, regrowth of Iris pseudacorus L. and Canna X generalis L. H. Bailey recovered better in the free-surface flow cells, while Colocasia sp. Fabr. Grew better in the sub-surface flow cells. Equisetum hyemale L. recovered equally well in both cells. This study was done in an area with milder winters than we have here, and thus the plant species used and the recovery may differ somewhat in our area.

• Mary Ann Rose et al. at The Ohio State University studied the effects fertilizer concentration and moisture tension have on the growth and foliar N, P and K content of container grown crabapple [Malus X zumi (Rehd.) 'Calocarpa'] and maple (acer X freemanii E. Murray 'Jeffersred'). They reported that whole plant growth, shoot length and whole plant dry-weight were greater when the plants were under low water stress. The fertilizer concentration had little effect on these components, but did have a significant effect on foliar nutrient content, as one would expect. Seasonal biomass accumulations were unaffected by the treatments.

• Three growth retardants' effects (ancymidol, paclobutrazol, and uniconazole) on flowering of container-grown mountain laurel (Kalmia latifolia L.) were studied at Virginia Polytechnic Institute and State University. Ancymidol (as A-Rest) had no effect on inflorescence at the concentrations tested, while paclobutrazol had a moderate increase in inflorescence numbers in the cultivar 'Freckles'. Uniconazole increased the inflorescence numbers in most of the cultivars when applied at rates of 50ppm or greater, as well as decreasing stem elongation.