A beautiful journey at any time of year, from mid-June the Hakone Tozan Line becomes a stunning journey through tunnels of lush green forest, over clear mountain rivers and past thousands of brightly colored hydrangea plants lining the tracks. In bloom just before the rainy season begins, ajisai (hydrangeas) are some of the most popular seasonal flowers of Japan, marking the beginning of summer and appearing in a myriad of colors and shapes. Loved for centuries, the Japanese name is believed to come from a gathering of blue flowers, although you can see hydrangeas in a practical rainbow these days.