Each year from late July through until late August, Kagawa's Sanuki Mannou Park hosts a Summer Festa event which is filled with fun summertime activities. There are around 15,000 cheerful sunflowers and 6,000 green kochia to marvel at, along with a water play area and kabutomushi (Japanese rhinoceros beetle) land for the kids -- the festival really does provide fun for the whole family.
For those who want to enjoy the sunflowers at their best, plan your visit for around late July to early August.