Overgrown means covered in plants that have grown wild. An overgrown garden, overgrown path, badly overgrown.
It describes neglect rather than abundance — an overgrown garden had a shape once and lost it, which is what makes the word slightly melancholy. Of a person it means grown too large for something: an overgrown schoolboy. Note that over- here means excessively, as in overcooked.
1adjectiveovergrownCovered in plants that have grown wild.
“The path to the old cottage was overgrown with brambles and nettles.”
overgrown is a quality of neglect.
From over- + grown.
Etymology from Wiktionary, CC BY-SA