I bought a couple of Oso Easy Double Red Rose. I have a hedge of double red knockouts in front of my house. I had a couple of 40 year old yews that bookended them that I cut down. What a nightmare. Tap roots were 8" thick a foot under ground. So, I'm planning on extending the hedge with these. I'm guessing/hoping these will look very similar or compliment well since it's an offspring of double red knockout. I'm rooting a couple double red knockouts that I could use instead. I know it's illegal to root, but I had one die on me and a double pink knockout die, so I think I'm entitled to two replacement plants. I think the oso is more bushy, so it would do better on and end than double red. Any thoughts?

Also, I found an old bag of super phosphate fertilizer. It's 0-60-0 slow release. Do you think it would good to plant with this? Or is this too much P?