Those would be the 'code' names (for lack of a better word) that these plants are patented under. RAD for the hybridizer, Radler. David Austin's roses are AUSwhatever, Kordes roses are KORsomething and so on in that manner.
Lowes here in Mich. had J&P roses at half price but the Knockouts were still at full price. I wanted to buy a J&P but the only ones they had left were not hardy in zone 5. I have a 2 yr. old Pink Knockout and it is virtually carefree. Gorgeous foliage and buds and it never stops blooming, a perfect rose bush except it has no fragrance. I love it all the same.
I went and bought the pink Knockout. At first I picked up the wrong one as the flowers of the red had faded to pink. I could not remember if Radrazz/Radcon was pink or red. After about 5minutes I was able to find a red flower in bud, get the correct name of the pink and locate one.
A local nurseryman recommended the knockouts for zone 6. Most say the Japanese Beetles might chew on a few flowers but leave the leaves alone. Linda