even if it does not rain
they plant on bamboo planting day-
a mino-raincoat and a rain-hat
降らずとも
竹植る日は
蓑と笠
-Matsuo Bashō (松尾芭蕉).
It was believed that bamboo planted on the 13th day of the 5th month would flourish. In China this day was known as 'Chikusuijitsu' (竹酔日).