Question
I planted a pink rose bush at the end of my house over 10 years ago.  Every year it has blossomed beautifully with medium size pink roses.  This year it began blooming red with the exception of a few pink roses.  What caused this strange phenomenon to occur?

Answer
Roses are budded onto what is called an undersock. This understock rose gives the top one more vigour. When a rose gets old, sometimes the understock which is more vigorous, sends up canes from under the graft union. The understock rose is called Dr. Huey and has semi double red flowers. If left it will take over your top rose. What you need to do is dig down alongside where the red rose is coming from and yank down hard to tear off the undrstock cane. Don't cut it off as this is like pruning it and will cause it to send out more canes. When you yank it off you cause a injury and when this injury heals it forms a scab which the understock can't grow from. Keep an eye open for anymore of these canes and do the same with them. Make sure they are the red rose so wait until it blooms so you don't make a mistake and hurt your good rose.