As I've mentioned here and on Garden Web, some private lists and elsewhere, some roses want to flower at the expense of growth. Rosarium Uetersen is notorious for blooming like a short floribunda and not climbing. One of my favorites of my own roses does the same. Annie Laurie McDowell LOVES to flower! Small plants of her will flower like crazy and take forever to throw the climbing canes you expect from her.
Here are a few photos of an own root plant I rooted just this year. She's tried to flower several times. It broke my heart to have to pick off the buds, but by not letting her flower, you can see the basal she's pushing out of the bottom of the original cutting. You can also see the smaller side branching she's developing.
The browning on the foliage isn't disease, but due to high heat and water stress. Smaller, immature plants will mature much faster in warmer pots than they will in the ground. Warmer soil has much more active bacterial action, digesting nutrients from the more organic potting soil and increasing the cellular activity of the plant. Giving it the warmer root space, keeping it properly watered, feeding regularly and not letting it flower will push the dickens out of it, forcing it to grow and develop the plant you expect much more quickly. I think the photos above of a plant less than six months old helps to prove my point.