How often does foliage spawn?
Solution 1:
From the wiki:
Vegetation re-spawns at a rate of one item per eight hours, except if all the spaces in your village are totally filled.
There can be a maximum of 40 obstacles at any one time, foliage, or vegetation, is counted as an obstacle, as are rocks, tombstones, gem boxes and special obstacles (Xmas or Halloween themed generally).
The chance of a certain vegetation spawning is as follows:
- Mushroom - 10%
- Bush - 20%
- Trunk (1) - 10%
- Trunk (2) - 10%
- Trunk (Fallen) - 20%
- Tree (Small) - 20%
- Tree (Medium) - 5%
- Tree (Large) - 5%
Note that rocks will not naturally spawn and tombstones will only be created when a troop dies. In addition special obstacles (Gem Boxes and other seasonal obstacles such as the Xmas Tree and the Halloween Cauldron) will ignore the 1 tile buffer around buildings and will spawn in any 2x2 space in the village.
Solution 2:
I believe It is random from my clash experiences.
It may help to know there is a pattern for gem yields from clearing foliage, as seen on the wiki:
Each obstacle that is removed will yield 0-6 Gems. The distribution is not random and follows the following repeating sequence: 6, 0, 4, 2, 0, 3, 2, 0, 0, 5, 1, 0, 3, 4, 0, 0, 5, 0, 1, 0. This means on average, each obstacle cleared yields 2 Gems. This pattern does not include the 25 gems yielded from the Gem Box, or the holiday themed obstacles like the Halloween