The Proto-Indo-European root is *bʰars- "projection, bristle, point" (the American Heritage Dictionary of Indo-European Roots says this is Pokorny bhar- 108 but I think they mean Pokorny bhares 109-110). The form *bʰrs-tio- became Russian борщ boršč "cow parsnip", due to its sharp leaves. This was one of the ingredients of borscht.
The form *bʰrs-ti- perhaps became Latin fastus "pride" from the notion of prickliness, and also fastīdium "disdain" (from *fasti-tīdium from fastus plus taedium "loathing"), borrowed into English as fastidious.
*bʰars- became English bristle, and also braird, a word for the first shoots of grass, corn or other crops. The OED quotes a Scottish proverb: "There is no breard like midding breard" (Kelly,
A complete collection of Scotish proverbs 1721). Midding is midden - I guess because corn grows well there.