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Chapter Two: Optimal greenhouse cultural requirements for Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’
Abstract. Phlox and Rudbeckia, popular native North American wildflowers, are grown for their showy inflorescences. Little cultural research has been performed on Phlox paniculata and Rudbeckia hirta cultivars for greenhouse production. Three greenhouse experiments with Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’ were conducted in Summer 2003 to determine optimal fertilizer rate, irrigation rate, and media type for each of the species. Four fertilizer rates (0, 100, 200, and 300 mg·L-1 N), three irrigation rates (Low: plants watered when average moisture content of medium reaches 20% or below; Medium: 30% or below; High: 40% or below), and four media types (Fafard 3B, Daddy Pete’s, Fafard 52, and Scott’s Sierra Perennial Mix) were evaluated in separate experiments. Height, average width, and quality ratings (on a scale of 0 to 4, 0=dead, and 4=healthy, vigorous growth) were measured for all plants. Media pH and electrical conductivity (EC) were also measured. Phlox plants were harvested at 6 weeks after treatment (WAT), and Rudbeckia plants were harvested at 4 and 5 WAT. Shoot dry weights were measured. The 200 mg·L-1 N treatment produced plants with significantly greater average widths, quality ratings, and shoot dry weights in the Phlox experiment. The 300 mg·L-1 N treatment produced plants with the greatest height, average width, quality rating, and shoot dry weight in the Rudbeckia experiment. In the Phlox irrigation experiment, the plants overall did not seem to be responsive to irrigation rate. Media pH and EC were also significant over time. At 6 WAT, the low irrigation rate had the highest EC levels,while the high rate had the lowest EC levels. For the Rudbeckia experiment, the highest irrigation rate produced the tallest plant with the highest quality rating and the greatest shoot dry weight. Media type significantly affected shoot dry weight in the Phlox experiment, with the Fafard 3B media resulting in plants with the highest dry weights. The Fafard 3B treatment also tended to have plants with the greatest heights, average widths, and quality ratings. The Scott’s Perennial Mix produced the plants with the greatest dry weights in the Rudbeckia experiment, and tended to produce plants with greater heights, average widths, and quality ratings in comparison to the other treatments.
Introduction
Phlox paniculata and Rudbeckia hirta are popular native floriculture crops. The cultivar Blue Boy is one of the P. paniculata cultivars that is closest to a true blue color (Nau, 1996). The cultivar Indian Summer of Rudbeckia hirta was an All-America Selections Award winner and has large golden orange flowers (Nau, 1996).Perennials are becoming increasingly popular additions to our landscapes. In 2003, the USDA reported that total wholesale value of floriculture crops was about $5.07 billion (Agricultural Statistics Board, 2003). The wholesale value of herbaceous perennial plants experienced a 1% increase (since 2002) to $620 million. A survey performed by Behe et al.(2001a) reported that in 2000, garden plant (including annuals and perennials) sales averaged $2.2 million out of average total gross sales of $2.4 million for the United States horticulture industry. The participants in that same survey reported Phlox and Rudbeckia as two species in the list of top ten perennials (Behe et al., 2001b). The plants were “graded”, 1=A or excellent,and 2=B or very good. Phlox received a 2.2 and Rudbeckia received a 1.8. Bedding plant sales have continued to increase for many years. Future sales depend upon the economy as a whole.A recession could help out the industry, keeping more people at home and interested in tending their landscapes.Traditional cultural practices (fertilizer, irrigation, and media) used with greenhouse crops are not always sufficient with many of our perennial crops (Pilon, 2002b). Not a lot of cultural information is known about perennials because relatively little research has been conducted on them until recently (Pilon, 2002a). Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’ are two such crops where little to no cultural information is available for their production in a greenhouse setting. Growing medium, irrigation, and fertilizer must be managed properly so that the minerals required for plant growth can be taken up by the plant in the correct amounts (Nelson, 1980). Therefore, the objective of the following experiments was to determine optimal fertilizer rates, irrigation rates, and media types for greenhouse production of Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’, in order to define possible guidelines for growers to follow.
ABSTRACT
ACKNOWLEDGEMENTS
LIST OF TABLES
LIST OF FIGURES
Chapter 1: Literature Review
Chapter 2: Optimal greenhouse cultural requirements for Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’
Introduction
Materials and Methods
Results
Discussion
Literature Cited
Chapter 3: Optimal PGR rates for Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’
Introduction
Materials and Methods
Results and Discussion
Literature Cited
Chapter 4: Effects of plant growth regulators on the severity of powdery mildew on Phlox paniculata ‘Blue Boy’ and Rudbeckia hirta ‘Indian Summer’
Introduction
Materials and Methods
Results
Discussion
Literature Cited
Chapter 5: Summary
Vita
