overgrown
adj.covered with too many plants or weeds because nobody has looked after it. You use this to describe a garden or building that looks wild and messy.
adj.covered with plants or weeds that have grown in an uncontrolled way. Often used to describe neglected land or structures; functions as a participial adjective.
“The old garden is completely overgrown with weeds.”
“The path to the abandoned cottage was so overgrown that we had to push through thick bushes to reach the door.”
“Decades of neglect had left the estate's formal gardens entirely overgrown, with ivy strangling the stone statues and wild grass obscuring the original gravel walkways.”
Typically used as a predicative adjective after 'is' or 'has become', or as an attributive adjective before a noun.
“His protests are surely the actions of an overgrown schoolboy, a man who knows nothing of responsibility, who is simply not realistic.”
“The most overgrown of all, what was once Camp 4, we reached by gunning the ATV off-track through the undergrowth.”
From over- + grown.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.