Osmanthus Fragrans Cultivars In East Henan Province And Their Suitability For Introduction

Osmanthus fragrans is one of China's top ten ornamental flowers.Combining attractive colors, strong fragrance,and elegant shapes,this Oleaceae species is widely used in Chinese gardens throughout its 2500-year cultivation history.It was introduced into East Henan province in the late 1980s.In this paper I provide a preliminary review of O.fragrans cultivars in this region.The datum were collected through an extensive field investigation and consulting experienced horticulture workers.I further discuss the species' adaptability in East Henan by analyzing the growth status, phenology,leaf physiological and anatomical characteristics of O.fragrans in Kaifeng,as well as the growth status of O.fragrans in Zhoukou and Shangqiu.East Henan province has 15 O.fragrans cultivars,including 3 of the Siji Group,1 of the Albus Group,6 of the Leteus Group,and 5 of the Aurantiatus Group.I describe the morphological characteristics of the cultivars in detail,providing a preliminary analysis of O.fragrans resources in East Henan.In Kaifeng,I examined effects of different levels of ventilation and water table on survival rate, diseases,pests,and flowering success of O.fragrans saplings of different diameters.I then discussed suitable environmental conditions for cultivating O.fragrans in the East Henan region.Based on the phenology of O.fragrans,I suggested the optimum time for planting this plant.I also discussed meteorological conditions conducive to flowering.I analyzed cold-tolerance levels of some cultivars by comparing their overwinter survival rates,changes in soluble sugar contents,and levels of leaf electric conductivity.In descending order of cold-tolerance levels,the cultivars are Sijigui,Daye Huang,Boye Jingui,Huangchuan Jingui,Chenghong Dangui,Quzhi Jingui,and Chuihua Jingui. Anatomical features support this ranking.I discussed applications of O.fragrans in landscaping projects of East Henan and problems thereof,suggested some solutions.The introduction of O.fragrans is overall successful in East Henan.Because the species is not entirely adapted to environmental conditions of this region,poorly planned large scale introductions should be avoided.In the future,cold-tolerance cultivars should be emphasized.We also must create microenvironments conducive to the species and provide better management.