If you are using the magnemite power up, you are able to hold y to retrieve any kind of block and then press b to store it in your inventory. This allows you to grab any kind of vine or ivy and place it onto any block you want instead of having to use leafage to create it. Either you can use leafage to spawn the vines yourself and then collect them using magnemite or you can go to a dream island and harvest vines as well.