I have read in several different places that you should not put rose cuttings into compost.
Is this because of the thorns or is there something in the chemistry of roses that has a negative impact?
I don't have any rose bushes, but whenever I get a bouquet of flowers, roses or otherwise, I toss them in the compost when they die (after cutting them up a bit, maybe into 2 inch lengths or so). They all break down just fine.
I'd be interested in reading the articles that advise this. There's no valid reason NOT to include rose trimming in your compost other than roses do tend to have a number of disease issues that an insufficiently 'hot' compost may not deal with adequately. And rose trimmings can be quite woody, requiring they be minced up well first before adding so that they will break down in a reasonable amount of time.
What was the reason given in these articles for why they shouldn't go in compost?
Personally, I can't see any reason why they would pose a problem. Ours have gone to the compost for years and other than some thorns that turn up now and then, no problems at all.
Anything that grows can be composted - except poison ivy and the like. ;)
The only reason I can think of is that if you don't shred them, they can take a long time to decompose. The thorns can stick you if they're not decomposed or shredded and that could be a nasty puncture wound (with compost in it). But I've composted rose cuttings plenty of times.
The thorns on the canes and the toughness of the canes are about the only valid reasons to not add rose canes to your compost, but even then that is not a very valid reason.
I have over 60 rose bushes, and I stopped composting the prunings, because the thorns take forever to break down. And with cubic yards of stuff every year, I ended up with a pretty high concentration of thorns in the compost - enough that even with gloves, it was very uncomfortable to work with - getting poked constantly.
I am not, by the way, replacing them as they die off. Some nice perennials w/o thorns that compost easily, thank you.
Some rose growers believe that deadly diseases such as Rose Rosette and Rose Mosaic could be transmitted from composted rose material. As no effective treatment has been found for either of these, folks tend to be cautious. I don't recall any hard evidence that transmittal through compost was likely.
Since getting my Harbor Freight 2.5hp electric chipper/shredder my rose prunings compost very easily. Best investment I have made.
The main reason that composting roses is not recommended is because most people's compost piles are not anywhere near hot enough to kill the blackspot spores. That, and thorns don't break down very fast at all.
If you are a compost whacko, however, which pretty much anyone reading this forum is, then you probably make sure your pile gets hot enough long enough, and diseases would not survive in your pile.
As far as the viruses rose rosette and rose mosaic, I would think no one's pile gets hot enough to kill viruses, but the little I know about rose mosaic suggests that it won't spread to new roses from compost. Don't know about rose rosette. Fungal diseases are the big issue as far as spreading in compost, but a hot pile should take care of that.
I have over 100 rose bushes and they are the main reason I now compost. I do however, chip the canes. What I do is leave them on the pile for months and then in the winter (we are late this year and doing it now) use a chipper to chip up the rose canes and any other prunings I have from butterfly bushes and other woody plants.
I do spray my roses with fungicide (sorry but it's impossible not to with roses)so I don't worry about disease. If I have a rose I suspect is diseased, I throw it out, I don't add it to the pile. I only buy virus free roses, so I don't worry about that. RRD, however, is a big concern among rose growers. As far as I know, I haven't had any with that disease.
I'm a passive composter, I take my cuttings and just dump them under a couple of trees in my back yard. Then in spring I turn the pile and take out anything that looks good and put that around my roses and other plants. The rest either gets chipped or just stays there for the new year. Today when I turned my pile there were many rose canes that were black and decomposing, but no where near ready. So I threw them in the chipper. Chipping takes care of the thorns, which is nice.