hmm...but nitrogen is the only nutrient that washes away very easily,and, as far as I know, roses need it as much as any other plant would...

The answer would be 'yes.' Urea is not pure nitrogen as was stated above, it is 46% nitrogen. What he might have meant is that it only contains nitrogen. Regardless, it is ok to us as a nitrogen source on roses. Also, it is not the only nutrient that leaches, but plants use it in large quantities and it is often limiting.

While urea does come from animal urine most all of the urea today is synthetic, a manufactured product and therefore not acceptable to an organic grower. If you are not an organic grower you can use it.

kimmq is kimmsr

But wouldn't a shot of nitrogen signal the plant to stop flower production and increase foliage?

Yes, roses need nitrogen. But only as much as any other flowering shrub, hence why I said they don't need much. A top dressing of compost is all my roses ever get and they do great.

Excess nitrogen leads to an excess of foliage growth. Which could lead to more pest and disease problems. Aphids especially love tender new growth. You want to use urea, go ahead. But as kimmsr said, it isn't considered organic and unless you want monster roses that flower sparingly you'll want to use the urea lightly.

Rodney