, Cindi ...
Do wonder about root competition, please ....
I know that early in my rose life, I heard that one of the things that roses do not like is "roses do not like root competition". Over the years, I've had enough roses show me that those rules always depend upon the rose, I often experiment to determine if they apply to "this rose; in this climate; in this site" rather that take it as an absolute given.
The "rule" about root competition is one of the reasons I made my post. Just looking at how far those junipers are placed away from the roses in my photos doesn't quite describe the distance, but I never considered their roots to be part of the problem with the rose because they truly were not planted close to the rose.
That slope crosses all the way across the back of my lot. Mrs. J. planted four different types of junipers and faced the slope with river rock for erosion control. Trust me, that old fence is NOT holding that slope in place. It's the roots of those junipers that keeps it from taking the house down the mountain to the river.
I do have other roses planted along that fence that are growing with various degrees of success and can provide photos. Some own root, some budded.
I can tell you that I found juniper roots extending into the house pad level at least five feet yesterday when I dug the rose hole for one of the other new roses. No, the roots were not as dense and I doubt if they will cause much difficulty for the rose and I will water differently and can monitor the issue differently, but the roots were there.
Maybe, we can enlist others from the tree forum and permaculture forums to give us some input to solve your erosion control problem with your pond. It's better to take a good look now than later. I think that kind of input is very important.