overgrown

adj

1. Having large numbers of plants which have become too big, and are hence spoiling the picturesqueness of a garden.
2. (attributive, derogatory, mildly)Having grown bigger without developing maturity or changing character.

   “He spends so much money on new technology: he's like an overgrown schoolboy buying toys.”

verb

1. (form-of, participle, past)past participle of overgrow