Spiky Bushes are similar to Saplings in some ways but they are a little more difficult to get to and deal with. Spiky Bushes grow natively in the Marsh Biomes and also damage the player's health by 3 points when harvested making them harder to get to and more dangerous to harvest.
Otherwise, Spiky Bushes provide Twigs similar to saplings. Further, they can be dug up and replanted. When they are dug up, they will still produce the Twigs along with the plant itself but without damaging the player. This provides a safe way of getting the twigs from the plant but at the expensive of Shovel usage.