Nitrogen defeciency in a rose bush
The leaves on a couple of our roses are a pale green, which, in this case, denotes a case of nitrogen deficiency. I know that it isn't an iron deficiency because...that bed had almost eight inches of partially de-composted organic material mixed into it about a year and a half ago. That organic material will - and has - used up a lot of nitrogen. So, I bought and used blood meal as a top dressing, into order to feed the roses.
As well, the other roses in that bed still have some good early foliage.
As a preventative measure, I think I'll 'plant' a rusty nail or two beside each rose bush. I'll find a few rusty nails and use a stick to push the nails down about three or four inches right next to the roots.. Another alternative is to put a few nails in a jar - and covered them with water, wait a week or two or three - and use the resulting rusty water as an iron 'tea' to pour at the base of the plants.
(No warrantees or guarantees offered or implied. YMMV. Batteries not included. My opinion is not offered as advice for you to follow. Do your own research. Do your own thinkin'... as if you were all growed up or sumpin'.)