2001 OSU LEARNING GARDEN OSTEOSPERMUM TRIAL RESULTS By Monica Kmetz-Gonzalez and Dr. Claudio Pasian Department of Horticulture and Crop Science, The OSU, Columbus, OH Last month, we reported the results of our Greenhouse Osteospermum Cultivar Trial conducted in late April. This month, we're presenting the results of our Garden Trial - an outplanting of all 45 cultivars to evaluate garden performance. On May 3, three plants per cultivar were transplanted from 4" pots into a freshly tilled ground bed in our annual trial garden area. Site location limited the number of replications. Spacing was 2 feet between plants. Watering was via an automatic overhead sprinkler system, and fertilization was with 20-10-20 (200 ppm N) as needed. Plants established well in the cool, wet conditions of May and the first half of June, atypical of the usual early growing season for Columbus, OH. This resulted in relatively good flower numbers at the time of the first evaluation on July 9. Subsequent evaluations took place monthly on August 13,September 12, and October 12. As of early November, plants were still flowering and producing a pleasing visual display. In a preliminary garden trial last year, plants fared well throughout the frost season, but succumbed after the first hard freeze in late November. Results presented here are from the August 13 (mid-season) and October 12 (end-of-season) evaluations (Table 1). Plants were rated on a 1-5 scale, 1= not acceptable and 5=exceptional. On August 13, an actual flower count per plant was performed. Data presented in the table includes flower number, foliage/vegetative vigor- listed as "plant vigor", and an overall rating. The table is ranked in decreasing order of the August 13 overall ratings. Of note, was the excellent performance of some of the Experimentals in the garden. 9304C was of particular interest. It was actually low in flower number outdoors, but had extremely attractive variegated foliage and very good overall vigor. The Symphony Series cultivars were the "everbloomers", blooming consistently throughout the season. It appears that they would benefit from a more continuous fertilization program to help maintain plant vigor. Our Osteospermum Garden Trial was very well-received by visitors to the garden area. Some cultivars exhibited tremendous "staying power" in their ability to produce new growth and flowers in constantly changing and somewhat extreme environmental conditions. As espected, during fall there was an inprovment in branching and flowering for most cultivars. Results presented in Table 1 are from the 2001 trial only. A new trial will be held in the year 2002. Stay tuned! For more information call Monica Kmetz-Gonzalez at 614-292-3848 or Claudiuo Pasian at 614-292-9941. See some pictures of the trial (Photo 1) (Photo 2)