Can roses go in compost?

QUESTION: Can roses go in compost? Someone sent me a dozen, and I hate to throw them away, even though they’re now spent. – Dara M

ANSWER: Not all parts of the rose plant are appropriate for composting, but you can add the flowers, soft green stems, and leaves of rose bushes to your compost bin, with a few exceptions. Parts of the rosebush other than stems make a good compost ingredient whether the roses came from your garden or the florist.

Fresh flowers function as a “green” component to provide your compost with nitrogen, and dried flowers are a source of carbon and serve as a “brown” compost material. The twigs and soft green branches of the rosebush will create some space around them in the compost heap, aerating it so that oxygen can circulate, which keeps the decomposition process moving along by making oxygen available to microbes.

The thorny stems of rose plants take a terribly long time to break down, so unfortunately they should not be added to compost. You should never add diseased plants to the compost heap, roses included, or you risk passing the disease along to next season’s plants when the compost is put to work in your garden. In a similar vein, you should not include debris from any plants that have come into contact with chemical treatments, whether they are roses or other varieties.  

Make sure to cut the stems and leaves into pieces so that they break down quickly and easily, and separate the petals of rose blossoms as you add them to the compost heap. Even the roots of rose bushes can be added to the compost pile, so at the end of the season, you can pull up the roots of annual rose bushes. Perennial types should be left in the ground where they are so they can return to bloom again next season.