We don’t have anything else to go on so I thought I would take a stab at trying to figure out what the registered parents of Rainbow Knock Out are,RadTee and RadRal. I used the search in helpmefind and for RadTee I came up with Softee as a posibility because Radler used Razz for knock out because it was in the name of one of the parents. And for RadRal it is for sure one of the Coral roses. I would guess Coral Meidiland as the most likely. And since he likes to self his parents to get the most disease resistant culitavars then I propose that the parents of Rainbow Knock Out are (seedling of Softee) X (seedling of Coral Meidiland). Another reason I am almost sure it is one of the Coral roses is the registered name of Rainbow Knock Out is RadCor which almost for sure names one of the Corals and a parent. Saw Rainbow Knock Out at the Tyler, Tx rose show last month and there were plenty of hips on them but I really was not impressed with the low growing shabby looking plants. Maybe they were not established yet.