The Ohio State University Learning Gardens 2003 Osteospermum Cultivar Trials By Monica Kmetz-Gonzˇlez and Dr. Claudio Pasian PART I. GREENHOUSE TRIAL 2003 marked the sixth consecutive year we conducted our Greenhouse Trial of Osteospermum. The Greenhouse Trial runs from January through mid-May. This year, we screened 18 cultivars from 3 source companies. Rooted cuttings were received from the participating companies between January 7 - 10. See pictures of each cultivar in Table 2 below. Cultural Schedule: 1/7 - 1/10/03, Week 0 Rooted cuttings received. 15 plants per cultivar were transplanted to 4.5 inch pots. Potting media: MetroMix 360. Greenhouse temperature: 72F day/night. 2/7/03, Week 4 Pinched plants to 5 - 6 nodes. 2/24/03, Week 6 Cold vernalization initiated: 46F day/night 4/7/03, Week 12 Temperature changed back to warm: 65F day/55F night 4/23 - 5/2/03, Weeks 15 - 16 Majority of cultivars at peak flower. Evaluations performed. Fertilization: Greencare 17-5-17 at 200ppm N 3 times/week Disease Problems: Pythium root rot was detected on a few plants in late January and continued at low levels through March. Plants were treated with Subdue Maxx and Clearys 3336 on January 31. Botrytis was detected in late February. Treatment with Phyton-27 took place on March 4. Also, as an environmental measure to slow down the spread of any Botrytis, relative humidity in the house was reduced through the use of fans. Height Control: No growth regulators were used in this cultivar evaluation. This provided a good indicator of the natural growth habit of each cultivar. Note on Conditions: Due to unseasonably warm outdoor day temperatures for this area of 60F - 70F for a two week period in March, it was difficult to attain the day time vernalization temperature of 46F for the desired period of 6 weeks. As a result, plants were at peak bloom 10 days to 2 weeks sooner than originally scheduled. Evaluations Performed: 1). PLANT HEIGHT to top of flowers (Table 1) was measured on April 23. Height is presented in centimeters and inches in parenthesis.  The table is ranked in order of shortest to tallest cultivar. 2). The main CULTIVAR EVALUATION (Table 2) was performed by the Trials Leader and Trials Coordinator on April 24. The table is ranked in decreasing order of the Overall rating. Evaluation Criteria:  Ratings were based on a 1 - 5 scale: 1 = poor/not acceptable, 2 = fair, 3 = good, 4 = very good, 5 = excellent. Plants were evaluated for the following characteristics: Flower: Flower quality and number; aesthetics, color, health and appearance. Vegetative/ Foliage, Habit/Health: Plant vigor, aesthetics/color, health, and appearance of vegetative portion of plants. Overall: Overall rating for all plants in the grouping, taking the above aspects into consideration. 3). The CONSUMER PREFERENCE EVALUATION (Table 3) was performed by our Annuals Team of Master Gardeners and by members of our Departmental staff on April 24. Plants were given an Overall (1 - 5) rating based on personal preference. Results: The top 5 entries in the Cultivar Evaluation as rated by the Trials Leader and Trials Coordinator were: 'Experimental V77-9B-3C', 'Malindi', 'Brightside', 'Symphony Cream', and 'Symphony Orange'. The top 5 entries in the Consumer Evaluation were: 'Brightside', 'Experimental V77-9B-3C', 'Symphony Lemon', 'Highside', and 'Symphony Cream'. Note that both 'Experimental V77-9B-3C' and 'Brightside' placed in the top 5 for both of these Evaluations. Trial Coordinator Comments: *** 'Experimental V77-9B-3C' was definitely a standout in the Greenhouse Trial. Some flowering occurred even before the vernalization period. Flowers started out whitish in color, and progressed to a silvery pink. Very attractive. *** 'Nasinga Cream' is a unique spoon-petaled cultivar. It placed reasonably well in the Cultivar Evaluation, but placed low in the Consumer Evaluation. However, when this plant was used in mixed combination plantings in containers, it was a standout favorite by all for the wonderful accent it provided. It was also the most compact of all cultivars, attaining a final height of only 22 cm; therefore it does not require the use of growth regulators during its culture period. *** 'Brightside' continued to be a "standard" favorite again this year. *** Even though the Symphony series does not require a vernalization period, (apparently a few of the experimentals are also following this trend), all plants in the Greenhouse Trial do go through the vernalization period together. Often by the time the majority of other cultivars are at peak flowering for evaluation, these cultivars are starting to turn past prime. They also tend to get more leggy in growth habit due to the extended growing period and lack of pruning. Take a view of our Greenhouse Trial: Photo  Acknowledgments: Appreciation goes to David Snodgrass, our Greenhouse Coordinator, for his excellence and expertise in growing this crop for us again this year. Thanks also to our student employee, Lana Mathewson and to our Annuals team of Master Gardeners - Joyce Gravlee, Ken Kotch, Kathy Krantz, Mary Straney, Juliet Taylor, and Bev Vogeley, who helped in all phases of the trial including the performance of the Consumer Evaluation. We also thank Nancy Taylor (Wayne Ellet Plant Pest and Diagnostic Clinic) and Dr. Steve Nameth (Ohio State Department of Plant Pathology) for disease diagnosis and recommendations. And we thank the following companies for their participation in this year's Greenhouse Trial: ECKE = http://www.ecke.com FIDES North America = http://www.fidesnorthamerica.com PROVEN WINNERS = http://www.provenwinners.com