pruning trees

[tryingarden5]

how do I prune a Tamarisk tree which has grown to one side

[lajohn]

pin very plump and juicy prunes on that side of the tree. or soak over ripe plums in water overnight and water the tree with that water. works a treat for the tree! good luck!

[Robinia]

They do tend to do that. Has it already flowered? If so, prune the branches with faded flowers on the widest side hard back to even it up. If it's a later, summer flowering one prune it early next yr (Feb-March).
If the light's prevented from reaching all sides or it's very close to something else it'll continue to grow lop-sided.