My light lilac roses, changed the color into light burgundy

It is not unusual for roses to "change color." A minor change occurs when cooler weather intensifies pink-to-red shades, or age and hot weather fade them.

The second type of color change is due to the fact many roses are grafted, so the branches are one variety and the lower root system is a hardier rose. If those lower roots sprout branches, they may appear different in leaf size, shape and flower color. They are more likely to have such sprouts when planted shallow, or if the top branches are all killed by cold temperatures.

The third change happens when one branch actually has a mutation affecting blossom color. Many of our colors started as a single odd branch, called a sport, such as the branch of pale pink roses on a Red Knock Out rose that became a new variety