The glacier lily's blooming period lasts about four weeks, typically from May to June.
Due to the low temperatures this year, the apricot trees' blooming period has been delayed to Tomb Sweeping day.
Results show that plant growth retardants have obvious effects on white orchid such as height reduction, more flowers and longer blooming period.
After "years of research", said the state news agency KCNA, it devised a chemical agent that could lengthen the blooming period by a week in summer or by 20 days in winter.
