Are the veins about the same color as the background? Is the discoloration fairly even over the plant?

If so, and if you are fertilizing with rotted leaves rather than rich compost, it could be a nitrogen deficiency. Leaf mold that has only rotted for one year can actually withdraw nitrogen from the soil.

But you said "several leaves." Where on the plant?

Yes, the veins are the same color as the rest of the leaf. The discoloration is not evenly spread all over the plant, but scattered on the leaves on some branches and not on others, or on some clusters of leaves, but not others. It seems to be more on the leaves that have emerged from buds at the tips of canes, but not as a rule.
I make compost from leaves, coffee grounds, paper, kitchen scraps, etc. However, the beds were covered with fallen rotting leaves from the Fall until last week, when I replaced them with two year-old compost from my bin.

It doesn't sound like any of the common deficiencies, then. Iron deficiency shows dark green veins against a lighter background, and oxygen deficiency shows yellow veins on older leaves.

Probably nothing serious, I'd guess.

I'd give it nitrogen, from whatever source you'd like to use - chemical fert, fish emulsion, other organic fert. Be sure to water well before adding it, and afterwards, and don't overdo it or you'll burn the plant - but yellow or pale green leaves are often nitrogen deficient.
Anita

Well, I was thinking N deficiency shows evenly over the plant; also there is slow and spindly growth. If the compost is mostly leaves and paper, that could be the problem, but if it's two years old, it should be at least slightly nutritive.

I will try some high N chemical fertilizer. The new growth is somewhat weak and slow. I seem to have some water soluble Miracle Gro around and will check the label for it's N content.
Would the problem with my compost be that the leaves and paper in it take time to get broken down and it is therefore low in N? Or are leaves and paper intrinsically poor sources of nutrients?
Thanks for all your help!!

I've got yellow leaves on a few of my roses. I think it's the result of a very warm early spring, then the freeze, and now 90 degree temps. My Don Juan is tri-colored. Some nice green leaves, some yellow leaves and some nice red new growth.

Miracle Gro has enough nitrogen, Miracid (or whatever it is now called) has more, or 1 TB of Turf Builder would be plenty (no herbicide). See if you get a response from this, you might learn something.

Go to the compost forum FAQ for a primer. For making ideal compost you need a balance between nitrogen and carbon, a certain range in the ratio. Leaves and paper are high carbon, low N ("browns"). Grass clippings, coffee grounds, and scraps are higher N ("greens"). If the mix is too "brown" it won't heat up much, and it takes two years for bacteria to eat up enough carbon for it to have fertilizer value. Meanwhile, the bacteria scarf up the available nitrogen for their own use. I'm not careful about my compost, which is mostly leaf mold, but I use additional fertilizer.

Buford: Yes, that is what my rose looks like. Yellow leaves, green leaves, and new red stems and growth. It's only the Sombreuil though. The hybrid tea, grandiflora, Darlow's Enigma, and Rhode Island Red (Fields of the Woods, Kocher Red?) are as usual.
Michaelg, I looked closer this am and found that the leaves do have green veins on many of them. So is it an iron deficiency?
Cemeteryrose, I did soak the roses with a Miracle Gro solution this am (contains 0.10 chelated iron) and will see what happens (NPK 15-30-15).
I was hoping this would not get complicated, as I like to keep things real simple, but I suppose I have to look into the compost situation now. My mix, if anything is more green than brown (lots of coffee grounds and garden and kitchen greens). Usually wet and slightly smelly while it 'cooks', and that's when I add paper or leaves that I keep in a bag adjacent to the bin. But the finished product was dry, crumbly, delicious black and odor free. It was from a 2 year old batch.

Compost sounds good. In cool, wet spring soils, available nitrogen from organic sources can be temporarily low, and some roses also have trouble taking up iron under these conditions. That's probably all it is. Some mostly-organic gardeners give roses a shot of manufactured fertilizer each spring for these reasons. The Miracle Gro for acid loving plants would be ideal, as it has both extra N and extra iron. There is probably not a deficiency in the soil, just temporarily in the plant.

Thank you!!!

If you don't want to use a "synthetic" source for nitrogen (such as Miracle-Gro), another "organic" way of supplying extra nitrogen is to use blood meal. If you find a garden center with a good supply of organic fertilizers, they will probably have blood meal.

That's a high nitrogen source that breaks down gently.