also: サボンソウ
noun
soapwort; Saponaria officinalis
A flowering plant whose leaves contain saponins and can be used as a mild soap.
サボン草の葉を揉むと泡が出る。
When you rub soapwort leaves, they produce lather.
庭にサボン草を植えている。
I have soapwort planted in my garden.
The Japanese name サボン草 (sabon-sō) literally means 'soap grass', from サボン (sabon, 'soap', from Portuguese sabão) and 草 (sō, 'grass/herb').