Madagascar periwinkle
Common ornamental plant with pink, white, or red flowers; also known as Catharanthus roseus.
Madagascar periwinkles are blooming in the garden.
Katakana spelling is standard for this plant name; usually written in kana.
Kanji spelling exists but is rarely used; the katakana form is strongly preferred.
From 日々 (にちにち, 'daily') + 草 (そう, 'grass, plant'), referring to its habit of blooming daily.