Tangle vines and vine shield both work in the same way
Quote:
Units become unable to move or attack until they free themselves. The chance to do so depends on the unit's strength and the growth dominion in the province. Specifically, a unit's Str + DRN must exceed the total of 18 + growth scale - (1 if waste) + (1 if forest)
|
So it depends both on terrain and growth sacle.