I have two rose of Sharon bushes that are about ten feet high and five feet wide they make a natural fence. I planted them about two feet apart originally. Now they fill the space between them Are they hurting one another.
Rose of Sharon Spacing
Certified GKH Gardening Expert
Two feet is somewhat close spacing for rose of sharon (3-5 feet is recommended), so they probably will end up smaller that they would have been if planted alone. But I don't think they will truly harm each other, they will just be smaller than usual. Making sure they get proper fertilization will help (just make sure to follow the fertilizer label and not to over-apply).