How long does it take to learn to perform a split?
It just depends on how flexible you are to begin with.
You will NEED TO STRETCH EVERDAY!
Stretching is key; if you practice everyday it should take no more than a week or two.
And remember: There are two types of splits, so learn both while you are at it.
Where is the best placement for springs in the vault springboard?
There are a lot of different placements for the springs depending on how much you weigh (the heavier you are the more spring probably needed), how strong your legs are, and just personal preference. I used to like two in the very back on the sides, two in the very front on the sides, and one in the middle of the board. I am doing a harder vault now, though, so i have two in the back sides, two in the front sides and two in the middle sides. Who knows...maybe i will have seven next year :)
I have honeysuckle growing over the entrance to an old cellar, and it grows rapidly every year. After it blooms, I cut it back to the desired point and it grows back every year. I use electric hedge trimmers. I am not sure what you mean about bushes. Mine are more of a vine, but are a rather old and large group that resembles a bush.