Yakuoin (薬王院) is a Shingon Buddhist temple located five minutes away from Seibu Shinjuku Line Shimo-Ochiai Station.
This temple was founded in the Kamakura Period (late 12th century to early 14th century).
Though it's not a large temple, the precincts are neatly maintained, and is a little famous for its more than 1,000 Chinese tree peonies which bloom in the mid- to late April.
Chinese tree peonies
There are some 1,000 Chinese tree peonies in the precincts, which bloom from mid- through late- April.
Opening hours are from 9am to 5pm and admission is free.