Q: A few years ago I planted yellow, pink and red roses. Now the blooms are all red. Why did they change color?

A: The most likely explanation is that you planted grafted roses and blooming sprouts have risen from below the graft union. To make a grafted rose, a twig from a beautiful rose bush is grafted onto the rootstock of an inferior rose. If you examine the trunk of your rose and find a swollen knot close to the ground, that is likely the graft union. If the branches above the graft union die for some reason, sprouts from the inferior rose will take over. If that rose was a common red one, you can see why your blooms might seem to have changed from yellow or pink to red.