2001 OSTEOSPERMUM TRIAL RESULTS By Monica Kmetz-Gonzalez and Dr. Claudio Pasian Department of Horticulture and Crop Science, The OSU, Columbus, OH Osteospermum are steadily but slowly gaining in popularity. However, the increasing numbers of new cultivars has made it difficult for growers to select the ones that perform well in a given geographical area. With this in mind, in 1998 we started trials to determine the feasibility of having osteo-spermums ready for Valentine's Day. Our research over two years led us to the conclusion that Ohio's environmental conditions make it necessary to force the plants at high temperatures in order to have them in bloom by mid-February. As a consequence of high forcing temperatures, plant quality was not acceptable. Since then, our trials test plants during the spring, the time when the majority of Ohio growers produce them. We have added garden trials in 2001 in order to see which cultivars perform better in our hot, humid summers. Rooted cuttings of 38 cultivars were received from the Ecke Ranch and rooted cuttings of 7 cultivars were received from Michell's on December 14, 2000. The following day, they were planted in four inch-diameter plastic pots using MetroMix 360. Plants were located in a greenhouse section at 72 F for plant establishment. Fertilizer applied was a 20-10-20, at a rate of 200 ppm Nitrogen 3 times a week. On 1/11, 2001, plants were pinched to 5-6 nodes. On 1/26, the temperature was lowered to 46 F for vernalization. On 3/9, the temperature was increased to 65 F Day/55 F Night. On 4/23, the majority of cultivars had reached peak flowering and a cultivar evaluation was performed . No growth regulator was applied; this allowed us to distinguish naturally tall from short cultivars. Ten plants per cultivar were rated using a 1 - 5 scale, being 1= poor and 5 = excellent (Table 1). Number of flowers, size of the flowers and plant height are presented in Table 2. Some cultivars reached full bloom earlier and were over their peak flowering. As a consequence, grades given by the evaluators to these cultivars were lower than what it would had been otherwise. Take a view of the trial: (Photo 1) (Photo 2) (Photo 3) (Photo 3)