Also, remember that a lot of growers feed their roses a diluted solution of fetilizer every time they water vs. one heavier feeding every month of 6 weeks, etc.
I've never fully understood why some people hose off all the soil from the roots of container nursery stock before they do in-ground planting. In doing so, all those millions of root hairs get broken off or destroyed and those are the first parts of the root system that take up water. It seems to me that when you do that you're setting the plant back by 6 or more months and doing more harm than good, not to mention wilting of the new top growth. Isn't it better to just break up that original root ball by X % instead of washing off all that original soil ? Just curious.