Rose canes are black after the winter

(Question)

Some of my rose canes are black after the winter. Should I cut them off, spray with anti-fungal solution or just wait and see if they start to leaf up

(Answer)

Thank you for contacting Toronto Master Gardeners.

Rose canes will show brown or brown-black discolouration from winter damage. After the long and cold winter we have had this may be more extensive than in previous years. Some of these black-ish areas are damaged, others may be dead. You will be able to tell which damaged areas are alive as those will have reddish buds on the stem. Roses should be pruned in early spring, as soon as there is no longer a risk of hard frost.  It is best to remove all areas with winter damage to keep your roses healthy and to promote new growth and flowers. Instructions for pruning roses can be found on our website in the Gardening Guides, here is the link: https://www.torontomastergardeners.ca/guidecategories/roses/

You also asked about fungal spray.  Roses, in particular older cultivars, are prone to some fungal diseases such as black spot disease, which causes black and brown spots on the leaves.  Since implementation of the Ontario Cosmetic Pesticide Ban Act chemical fungicides are no longer an option.  Fortunately most newer rose cultivars are much less susceptible to these diseases.  You can try to prevent or limit the spread of black spot rose disease by avoiding watering from above (avoid watering the foliage), and removing and discarding in the garbage any affected leaves. You can find more information on recognizing, preventing and dealing with fungal disease of roses here: https://www.rbg.ca/caring-for-roses/

Happy gardening!

2022.04.27