overgrowth

Short definition from Wiktionary

Noun

1. 1
   A usually abundant, luxuriant growth over or on something else.
2. 2
   A usually abundant, luxuriant growth over or on something else: A tangle of growth occurring at the top of trees involving vines and branches, common in jungles.
3. 3
   An excessive growth or increase in numbers, as in a population of weeds or microbes.
4. 4
   Excessive size; usually caused by over-production of growth hormone from the pituitary gland.