valley of flower trek in one of the most beautiful trek, which also recognised by UNESCO as world heritage site in 2002, how to reach Valley of flower trek, take a bus, car or flight to Haridwar, from their you can take a bus to Dehradun, which will take 7-8 hours, the best time to visit Valley of flowers trek is June to October as this time of the year you can see the flowers bloomed. This is not a difficult trek.