Can you regrow these roses by getting a cutting and rooting it?
Yes you certainly can. They are patented rose bushes though, so if we do such a thing we are hurting the patent holders financial well being. Many will say it is okay as long as you are only doing it for your own rosebushes and not doing it to sell them to others. There are older rosebushes that no longer have such patent protection that are okay to root and grow. Just keep in mind that we really do not want to hurt the financial well being of those whom bring us the beautiful new roses each year, as that will eventually lead to fewer being able to supply the roses and even higher prices. Here is a link to an article for you as well: http://www.gardencentermag.com/article/grower-caught-illegally-propagating-knock-out-roses