Evidence is growing that people exposed to environmental and mental stress benefit from having plants in their communities and from working with those plants in gardening and related activities. The benefits to the community range from improved social interactions to reduced littering. Feelings of self-confidence and self-worth are improved. Economic conditions can be improved: vegetable production reduces the need for individuals to spend money on food, and community improvement initiated by flower gardening increases property values. Some of these benefits are well-documented, while others are primarily supported by a long history of anecdotal evidence. More research is needed to fully document the importance of community gardening efforts and to justify expansions in these programs.
Virginia I. Lohr
Conducting research with human subjects involves many of the same issues involved with conducting any type of research. As horticulturists, we are aware of the range of variability that can be introduced when working with living organisms. This variability can come from environmental influences as well as genetic variation. These can be major factors when conducting research with people as well. Research with people also introduces complicating interactions between the researchers and the subjects. When working with humans as subjects, federal regulations must be considered; these regulations are even stricter when the research involves youth. These additional factors, which should be considered when designing studies to understand the impacts of plants and plant programs on youth, will be discussed.
Virginia I. Lohr
Researchers and practitioners have been aware of the importance of plant diversity for many decades. The Irish potato famine and dutch elm disease (Ophiostoma novo-ulmi) are examples of problems resulting from lack of diversity. Emerald ash borer (Agrilus planipennis) has renewed concerns over these issues, yet little has been done to increase diversity in landscape plantings. Urban trees are becoming more uniform genetically because of cloning of preferred cultivars; thus, they are losing potential resiliency to stresses at a time when these threats are increasing. A survey on plant diversity distributed to wholesale nurseries in Washington State showed that most respondents were aware of the issues, but lacked an in-depth understanding of them. This article presents additional data from the survey. Respondents reported that lack of consumer demand was an issue. Those with more education exhibited a deeper understanding of the risks from low diversity among landscape plants. Instructors in horticulture and the plant sciences should be more involved in teaching on this topic.
Virginia I. Lohr
Many undergraduates major in horticulture because they love working with plants. When they hear research that documents how people respond-to plants, some students -begin to understand why they have responded positively to plants, and they want to learn more about the topic. This paper 1) discusses the potential to use students' excitement about human issues in horticulture to teach principles that educators consider important components of a baccalaureate degree, and 2) presents the case of one student to demonstrate how it can be done.
Virginia I. Lohr
Horticultural crops are being affected by weather extremes consistent with predictions from climate change models. Impacts include crop losses and extended growing seasons. Negative effects on crop productivity are predicted to vastly overwhelm any positive effects. Students who graduate from our programs will need additional knowledge to succeed compared with those trained in previous decades. To determine the extent to which higher educational institutions across the United States are educating students about these issues, a survey was conducted to gather information on the incorporation of climate change literacy in horticultural curricula. Most programs do not currently offer classes with “climate change” or “global warming” in the formal title or description, but many instructors are including at least some information related to climate change in specific courses they teach. Instructors of courses in fruits, vegetables, or turf, and instructors who do not teach at 1862 land-grant universities, are more likely than other instructors to include content related to climate change in their courses. Instructors who do not have tenure and instructors who teach plant identification courses are more likely than other instructors to have increased the content on climate change in their classes over time.
Barbara Berge and Virginia I. Lohr
Studies have shown that many people prefer landscapes with vegetation over those devoid of plants. Few studies have looked specifically at adolescents or people of different ethnic heritages. Understanding preferences of such groups could help in designing horticultural education programs for these populations. In this study, high school students were asked to rate their preferences for a series of plant-dominated and urban-dominated slides.
Students generally gave higher ratings to the plant scenes than the urban scenes, indicating that they preferred the plant scenes. Their preferences were similar to what would be predicted from studies with adults. Hispanic students rated urban scenes and formal plant scenes, such as a garden with sculptured shrubs, significantly higher than did Anglo students. Hispanics rated informal scenes, such as a deciduous forest with no ground cover, significantly lower than did Anglo students.
Virginia I. Lohr and Caroline H. Pearson-Mims
The effect of organic matter addition and irrigation rates on the growth of bedding plants was found to vary with species. Marigold and sweet alyssum were field-grown with or without added peat moss under normal or 50 percent reduced irrigation.
Regardless of organic matter treatment, marigolds with reduced irrigation were shorter than those with normal irrigation. Under normal irrigation, adding organic matter had no effect on height. Under reduced irrigation, incorporating organic matter was beneficial to marigolds: plants in these plots were 10% taller than plants under reduced irrigation without added organic matter.
Sweet alyssum, a relatively drought-tolerant plant, was wider under reduced than under normal irrigation. It did not benefit from added organic matter: plants grown with added organic matter were 17% narrower than those without added organic matter, regardless of irrigation level. Blanket recommendations to add organic matter to conserve water should be avoided.
Virginia I. Lohr and Caroline H. Pearson-Mires
Cut flowers of eight cultivars of Rosa hybrida L. were held in preservative solutions containing up to 4 mg F-/liter. Leaf diffusive resistance was increased by holding flowers in F-solutions. In most cultivars, fresh weight gain was decreased, the degree of flower opening was affected, and visual symptoms of injury were noted in the presence of. F- in the holding solution. Damage at 2 mg F-/liter was almost as severe as at 4 mg/liter. Number of days to petal abscission or bent-neck was shortened by F- for `Samantha' and `Bridal Pink'.
Virginia I. Lohr and Caroline H. Pearson-Mims
Community involvement is critical for the continued vitality of the urban forest. To encourage this involvement, an understanding is needed of what promotes shared stewardship as well as of different cultural perspectives regarding trees. A survey of the general public in 109 large metropolitan areas across the continental U.S., a culturally and ethnically diverse group, was conducted. Two thousand adults were surveyed to assess the extent of their childhood experiences with nature, their current attitudes toward urban forests, and their demographic backgrounds. Respondents were questioned particularly about their earliest experiences with nature and their current understanding and appreciation of the urban forest. Other researchers have examined the relationship between childhood contact with nature and attitudes toward nature among professionals in environmental fields, but this relationship has not been explored in the general public. Correlations between survey respondents' memories of childhood contact with nature, their current perceptions of the urban forest, and the influence of their cultural and ethnic backgrounds will be presented. For example, respondents who reported very easy access to nature as children were likely to agree strongly that trees should be planted in business districts to reduce smog. Results from this survey may be applied in programs to teach children about trees and gardening, thus better tailoring these programs to engender future appreciation for the urban forest. Raw data from this survey will be made available to other researchers.
Caroline H. Pearson-Mims and Virginia I. Lohr
Cut `Samantha' roses (Rosa hybrida L.) were placed in deionized water or a 20-mm Ca(NO3)2 pulsing solution for 72 hours. Flowers then were held in preservative solutions containing 0 or 4 mg fluoride/liter. Fresh weight gain, solution uptake, degree of flower opening, and flower longevity were reduced in the presence of fluoride in the holding solution. Visual symptoms of injury and reduced flower quality also were noted in treatments with fluoride. Pulsing improved fresh weight gain and degree of opening of flowers held in solutions containing fluoride. Pulsing also delayed the onset of visual symptoms of fluoride injury. Water uptake for flowers that were pulsed and exposed to fluoride was not different from uptake for flowers exposed to fluoride alone. Flower longevity for roses in all treatments was increased by using the calcium nitrate pulse, but pulsed flowers in fluoride did not survive as long as the control flowers.