Abstract: 【Objective】 To provide references for the cultivation and demonstration of ornamental sunflowers in coastal areas of Jiangsu. 【Mothods】 Self-selected ornamental sunflower Yankui No.3,Yankui No.4 and Yankui No.5 were tested using a random block design. The flowering characteristics of the ornamental sunflowers and the relationship with sowing date were investigated by setting two sowing dates in summer and autumn. 【Results】 Sowing dates and varieties had significant effects on the initial flowering stage,flowering time and flowering ratio of discs on secondary branches of ornamental sunflower（P<0.05）. Compared with summer sowing,autumn sowing significantly prolonged individual flower trays,individual plants and the flowering period of population（P<0.05）.Yankui No.3 had the longest flowering time in autumn,with 29.9 and 38.6 flowering days per plant and population,respectively. The flowering order of ornamental sunflowers was generally shown as the main disc first,followed by the main discs of side branches,which bloomed from top to bottom,then starting with inverted 1 inverted 2.The ratio of discs on the secondary branches varied according to the sowing date,variety and location of the lateral branches. Overall the ratio on summer sowing was higher than autumn sowing,and the ratio on inverted 1 branches was higher than the inverted 2 branches. 【Conclusion】 Sowing Yankui No.3 in autumn in the coastal areas of Jiangsu could fully realize its ornamental potential.

Key words: Ornamental sunflower, Flowering characteristics, Disc, Sowing date, Lateral braches