Hi Nadia,

I'm sorry to hear about your trees!

Upright junipers can be prone to getting splayed out in heavy snows here, and  once the branches are bent out they usually will not return to upright positions.

Fortunately, though, judicious pruning can help not only correct some of the horizontal growth but make the tree more resistant to this happening again.  Especially for young trees like yours, early training can set up the tree for a long life of good branch structure.

For the branches that are already growing too horizontally, cut them back enough to reduce the leverage so that they can return to a more upright growth form.  Cut back to a crotch in the branch, where smaller branchlets are growing from the larger branch.  Ideally, choose a branchlet that is growing in the direction you'd like the branch to grow.

To help make the tree more resistant, selectively shorten branches back to crotches, in the same fashion, focusing on those that are growing in vigorous competition with the leader, or main trunk in the middle.  by shortening them, you reduce the speed of their growth and enable the main trunk to develop a strong branch union.  The branch will also develop a better width:length ratio, making it more difficult to bend down under a load.

Be careful to remove no more than is necessary, and never remove back further than where green branchlets are growing--junipers will not sprout from bare branches, and you will be left with unsightly holes in your trees!

Tying the branches up is usually not recommended, as it is labor intensive not only to get it done in the first place, but the ties must be adjusted regularly to accommodate tree growth.  Over-supporting a tree also reduces the natural strengthening that the tree would undergo, making limbs weaker in the long run.  

I hope this is helpful!

Cordially,

John