Cherry blossom is three weeks of it. Flip through the other forty-nine — and watch what's in bloom move up and down the country.
The calendar is the way in. Underneath it sits the ordinary thing — search, filter by month or flower, and open any of the 429 spots.

Photo Ocdp (CC0) — via Wikimedia Commons
For three days each May, private gardens across Nagareyama open their gates to visitors; 2026 was the 19th year, with 15 gardens taking part. It falls in rose season, and many of the gardens are planted with roses. Free, with no booking needed; the city website publishes a map of the gardens.