1) Brush 2) Brushwood 3) Bush 4) Bushes 5) Coppice 6) Copse 7) Greenery 8) Scrub 9) Shrubbery 10) Shrubs beneath trees 11) Thicket 12) Underbrush 13) Underwood 14) Vegetation 1) Brush 2) Brushwood 3) Bushes 4) Copse 5) Plants 6) Twigs 7) Underbrush 8) Underwood 9) Vegetation 
Undergrowth usually refers to the vegetation in a forest, which can obstruct passage through the forest. The height of undergrowth is usually considered to be 0.3 – 3 m (1 – 9 ft.). Undergrowth can also refer all vegetation in a forest, which isn`t in the canopy. ...
• (n.) That which grows under trees; specifically, shrubs or small trees growing among large trees.
low-lying vegetation or small trees growing beneath larger trees; underbrush. · the condition of being undergrown or undersized. · short, fine hair underlying longer, outer wool or fur.