Tree grindings in the soil (or more pointedly the microbes) can leech nitrogen to break it down, but tree grindings on top of the soil shouldn't steal too much, especially when you consider most tree grindings have their own source of nitrogen (leaves) ground up in the mix. Adding fertilizer between the mulch and roses should feed both the microbes and the roses.

This past summer my one rose did not thrive like it usually does and, as you described, had a fair amount of yellowish leaves. When I apply tree trimmings to the bed it resides in, I keep the mulch back about 6-10" from the rose.

I attributed the poor health of my rose to a few things: 1) I don't often fertilize. I never was much of a rose bush person and when I read a while back how often roses in Florida should be fertilized, I became even less of one, but as this was a house-warming gift from my dad and his wife, I have taken care of it. 2) Last year the rose bush was a little crowded. I had a pentas on one side that did very well over the summer and some mystic spires salvia on two other sides that got quite thick as well, this resulted in poor air circulation around the rose bush, something that is a must for Florida's hot and humid summers. And 3) My rose bush is likely not on Fortuniana rootstock. As I stated, it was a house warming gift, but it was purchased in mid-state South Carolina. Frankly I am a little amazed it has done as well as it has down here. Similarly to tomatoes, roses can be affected by root-knot nematodes, which the Fortuniana rootstock is resistant to. I know from tomatoes I have dug up that I do have root-knot nematodes in my yard, so it wouldn't surprise me if my rose bush has been affected. In early spring I plan to dig mine up, rinse the roots of any soil and check for/remove any affected roots. I will then put the rose bush in a larger pot to protect it from future nematode attacks.

I am no rose expert, not by a long shot, but I hope my few insights helps you i figuring out your issue.

Michael gives some good info above.

I understand that wood mulch does not 'take out' nitrogen from soils, but it can alter soil pH, which can affect nutrient uptake. Also, keeping mulch away from the stems of woody plants is recommended, since it can cause problems.There is a soil, compost & Mulch forum w/ many experts & good info in the FAQs. And there is a Roses forum w/ even more specific info/discussion.

Seems like the problem was lack of fertilizer - not necessarily thick mulch. Thinking a liquid fertilizer would penetrate thick woody mulch, but granular would have to be applied below the mulch. IOW, pulling back mulch, applying fertilizer, then replacing the mulch over it. Foliar feeding is also a good supplement.

Never overlook the need for minor nutrients with roses. Have you checked the iron? You may want to consider sending some leaf samples for analysis to see what the lacking nutrient(s) is/are.

I've done a complete soil analysis(but not a leaf analysis). I've been in close contact with my agricultural agent who suggested applying the heavy doses of nitrogen. I've tried several foliar nitrogens...that was pretty much a trial and error experiment after much research but nothing definitive. But that didn't seem to help.

Pulling the mulch back on over 40 roses bushes to apply fertilizer isn't going to happen. If I was a man...well, maybe ;-). Sounds like a good ideas except for the burning of the roots part.

Posting on the rose site is a no go! What a bunch of egomaniacs!

I will continues to apply ammonium nitrate when it warms a little.

I suspect Michael may be right about nematodes. What are the chances this couple has all 40 shrubs on Fortuniana root stock? After a few years, nematodes take their toll on rose bushes. You can improve things a little with nitrogen and minor elements, but you can't repair roots that have been slowly and severely damaged. I've used wood chip mulch in my garden for years. Although it's best not to use more than 2-3 inches of mulch on anything, and it definitely should be kept away from trunks, done right, it will improve the soil markedly as it breaks down. We fertilize very little and very weakly when we do, and the wood chips have changed our soil from sand to organic loam. No problems with robbing nitrogen here. If it does so a little at the soil interface, it is way more benefit than detriment in any garden. I will never use anything else as long as wood chips are available to me.

Oh no this Ole myth rearing its ugly head. Chips may take some nitrogen (minimal) to decompose, but where does it decompose? Right where it's placed. It comes fulL circle folks so not hurting plants.

I think Anna has a point about all the roses not being on Fortuniana rootstock, and even those don't live forever. I was taught that Dr. Huey rootstock roses live 3-5 years and Fortuniana live 10-15, so unless they are old garden roses, they may just be dying of old age. Did your soil test find enough magnesium in the soil? Our soil has absolutely no magnesium, and I've found that many times when a plant that is being properly fertilized starts yellowing, it has hit hardpan and needs some Epsom salts so it can grow new feeder roots.