I've climbed a few mountains in my time, both in New Zealand and in Japan, but Yume-no-Teien is one of the most beautiful mountain locations I've seen. It was discovered by the owner of a nearby guesthouse when he was climbing Mount Kitaokusenjodake, and he gave the area its rather romantic name. The plants growing there are wild and completely natural, but there is an amazing variety, and it really seems like a garden. It is only 15 minutes walk uphill from the car park, and even in August it was blessedly cool up there. I hope I can go back there when the rhododendrons are blooming!
Dream Garden on Top of the World
Yume-no-Teien in Yamanashi Prefecture
