also: のぐさ
noun
wild grass; wildflowers
Refers to grasses and herbaceous plants growing wild in fields, roadsides, or mountains. Often includes small wildflowers. The reading やそう is standard; のぐさ is rare and may appear in older or poetic contexts.
春になると、道端にいろいろな野草が咲く。
In spring, various wildflowers bloom along the roadside.
このあたりでは食べられる野草がたくさん採れる。
Around here you can gather many edible wild plants.
山菜 specifically refers to edible wild plants harvested in mountains, while 野草 is a broader term for any wild grass or herb, not necessarily edible.
雑草 means 'weed', often with a negative connotation of unwanted plants in gardens or fields, whereas 野草 is neutral and simply describes wild plants in nature.
Compound of 野 (field, wild) and 草 (grass, herb). The reading やそう uses the on'yomi of both characters, while のぐさ uses the kun'yomi. The on'yomi reading is now standard.