I have a tunnel covered in roses. It has been there for about 12 years and always gave 1000's of roses. This year it began sprouting and suddenly the leaves turned yellow and on cutting a branch I see that it is dying back. We did have a very cold winter this year with -18°C in the garden during 3 weeks. What can I do to save them? Many thanks.
You may not be able to as the winter kill may have too strong a hold upon them. However here is something you can try that has worked for me at times. Water all the roses with some water that has both root stimulator and a product called Super Thrive in it. Water them with such mixture the next 5 times they need water. You can also rough up the soils around the base of each rosebush and sprinkle One Cup of Epsom Salts around the base of each rosebush. Work the Epsom Salts into the soils a bit and water well. This also works for a great Spring "kick start" for the rosebushes.