also: つちゴボウ
noun
great burdock sold with soil
Refers to burdock root sold with soil still attached to preserve freshness. Often seen in greengrocers or farmers' markets.
See also: 牛蒡
八百屋で土ごぼうを買ってきた。
I bought some soil-covered burdock at the greengrocer's.
ごぼう is the general term for burdock root, while 土ごぼう specifically refers to burdock sold with soil still on it.
Compound of 土 (つち, 'soil') and ごぼう ('burdock'). The spelling 牛蒡 is the kanji for burdock.