Photomorphis Textural Borders are .png files and are transparent in the areas where there is no detail. So if the border is one of the black borders, that means that you can hold down the Command Key on a Mac or the Control key on a PC and click on the border layer to make a selection of that border.
1. Make a new blank layer
2. Make a selection from the border layer as I describe above
3. Select the blank layer
4. Select a color from the color picker (change your foreground color to the color you want
5. Use the Option Delete keyboard shortcut to fill the selection with your selected color on the new layer.
You can then play with the blending modes and opacity controls to adjust the color and effect to your liking.
If the border has some color tones in it already, you could just clip an adjustment layer to that border for example a Hue/Saturation adjustment layer clipped to the border layer, then playing with the controls until you get a result you like.
You can use any combination of these two techniques to work with adding or changing colors for these borders.
Remember, there are many ways to accomplish this. Too many really to describe here, but play with the layers blending modes, clipping adjustment layers, creating selections of the border and adding color to it, or using that selection on an adjustment layer over the top of your image and applying it with a different blending mode.
Related: See all the Photomorphis Textures and Borders