It really depends on how big your roses get. If a mini rose at mature age only reaches a foot in diameter, and the one next to it reaches 2 feet in diameter, then yes a foot. But if two roses next to each other max out at one foot each in diameter, you might want to shoot for six inches apart. You need to know how big your mini rose is going to get. I have mini roses that are now 12 feet wide and 15 feet tall. So it's very important to understand the potential size of your mini rose before planting.
Alan
