I'm asking for a friend who is puzzled. She purchased this dahlia five years ago. The first four year all the tips of the petels were uniformly white as she expected. She divided the tubers at the end of season last year. This year they have been coming up with random white tips.

Any thoughts on why this happened? Is it a type of reversion? Or perhaps something caused by the division?

Someone suggested it might be caused by something in the soil she added last year. Dahlia example 1 Dahlia example 2

  • I ran into my friend again today, and asked her for an update on her dahlia's. She said that as the weather cooled down the white mottling went away. Any chance it was from heat? She was growing then in large black pots, in a very hot place in her yard. She's going to try moving them to a cooler location next year.
    – Ben
    Commented Dec 20, 2018 at 3:12

2 Answers 2


It's just a blip in the genetic code and is not particularly unusual, especially in colour break flowers. These often occur naturally, and are selected for breeding to try to maintain whatever form of colour break has occurred, but, over time, especially in dahlia as the tubers increase, the DNA may alter again and the colour break pattern becomes more random. It's nothing to do with the soil, and there's nothing to be done about it I'm afraid. Your friend may find, eventually, that one section of the tubers she has split does produce the original type of flower - if that happens, then isolating the particular tuber its coming from, separating it and growing it on separately might give a plant ongoing that is not so random.

  • Still puzzled as to why the act of dividing the tubers would cause the plant to start acting differently. I know the original start my friend had was a division from a division and no revision happened either time.
    – Ben
    Commented Aug 24, 2018 at 3:51
  • It may be nothing to do with the act of dividing the tubers, even without dividing, this can just happen anyway. As the tuber grows, the genetic code may alter slightly and this might have happened anyway - or the damage caused by dividing could,this time, have caused a disruption in a tiny piece of DNA. Both these things happen in humans and every living thing as they get older - DNA does not always replicate itself absolutely correctly over time, though the alterations may be subtle and not particularly obvious (though not in this case, clearly, since its affected the code for colour)
    – Bamboo
    Commented Aug 24, 2018 at 8:45

Gosh, this is normal. Especially with these hybrids. I would not worry about this at all. Yes, it is reversing to previous DNA a bit? But probably won't ever stop having white tips.

What exactly do you mean that she changed her soil last year? PH change could be a factor. Are these Dahlias in the garden or are they in pots? Does she dig up and bring the bulbs in each winter? Does she have to because she's in a zone with real winters? What does she do for fertilizer?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.