Question
My husband insists on pruning my 2 climbing roses to mere nubs every spring. I thought we should let them be natural. What would cause yellowing of the leaves? Thanks for your time.

Answer
There are two types of climbing roses and the ones that are bred for being a climber can be whacked back every year if you want to. The problem there is that they use up a lot of energy growing back which could be  used to bloom better. So they make growth at the expense of making flowers. The other climbers are sports of bush roses and if you cut those back hard, then many times they will just revert to growing like a bush rose again. Yellow leaves can be caused by many things. Too much water or not enough water. Hot roots which put the rose under stress.  It also depends where the leaves are yellowing at the top or at the bottom. The base yellow leaves could just be the old ones that are dying off. Climbers love cool roots and even do better with a mulch all around the base. It gives them a cool, damp soil. Perhaps it is the severity of the pruning which could put them into a sort of semi shock until they start to grow again. Most hard cutting will put a rose under stress and this will cause lots of yellow leaves until the stress is taken away.