The plum flower (Ume) festival held Mt. Tsukuba (Tsukubasan). The plum forest is located at 250m high on the Mount Tsukuba has 1000 plum trees and overlook the city of Tsukuba. On a sunny, clear day Skytree in Tokyo or even Mt.Fuji can be seen up there.

Located in the southern part of Ibaraki prefecture, easily accessible from Tokyo area, Mt Tsukuba or Tsukubasan has been popular mountain where people can enjoy hiking, sightseeing and Onsen bathing.

Mt.Tsukuba Plum Festival 
Tsukubasan Umematsuri

February 14th 〈Wed〉 -  March 21st 〈WedNational holiday  2018
Location: Mt.TsukudaTsukubasan Mountain〉in Tsukuba City, Ibaraki Prefecture

Offical Website
http://umematsuri.jp/

Related article in digi-joho TOKYO
Tsukubasan Mount Tsukuba in Ibaraki
http://tokyo.digi-joho.com/trips-excursions/tokyo-surroundings/86-tsukubasan.html