Question
In a friend's garden in southern Italy a rose plant has spontaneously developed  two twin flowers on a single stalk, as if the developing flower bud had undergone a duplication. Could you tell us whether this is a common or exceptional event? With many thanks. Fioretta Palombi

Answer
What you describe is called proliferation of a rose bud. It is not unusual but can be a rare occurrence in private gardens. The reason for it is not fully understood by the rose world. Rose breeders have suggested that the cause could be a hormonal imbalance or a viral disease. They also think weather conditions in the spring may have an effect. Some roses, especially the very old garden roses which are very double and have a eye or pip in the center, often proliferate every spring. It is written up in books as far back as the 18th century. Rose buds are very vigorous, especially the ones at the tips of the canes. This vigour is caused by the apical cells multiplying quickly. The thinking now is that these cells go wild and do not stop diving when the flower is made but continue the process. The fact that you have a rose which has done it, suggests that it will probably happen again next spring.Simply cut off the area below the problem and it will return to normal.