Why would a yellow rose bush produce red roses?

I've had 2 yellow climbing roses for 4 years. This year when they bloomed they were red! (One was multicolored pink). We had a severe drought last year. Did that effect it?

Why would a yellow rose bush produce red roses?
I can't give you the reason int technical terms, but here is your answer.



Changing colours would suggest that the rose was a Hybrid. A very technical science these days, but imagine that the rose you have was created by cross-pollination of two different rouses. The seeds collected from then would, therefore, produce a hybrid ... traits from two roses come together and create another "different" rose, the colour being one of the obvious changes otherwise you wouldn't have a hybrid.



It does happen that a hybrid can revert back to "parent", in other words reverts back to one of the two single rose from which it was hybrid from. Of course, it could have been hybrid from any amount of roses to get where it was, but it'c colour has reverted back to one of those, and that one would be its original form an colour ... "back to parent"; in other words reverted back.



That would explain your rose having changed colour. Not very technically answered, but that is the practical answer :)



~F~
Reply:Gardening fool 42 (see below) has the only correct answer here I've seen this happen with both roses and fruit trees. Report It
Reply:it is because of its genes.



there are two types of genes: the ones who will define the outlook of a plant. these overpower the ones whose character do not express the outlook of the plant.



in your case, the color yellow is a weak characteristic so under certain curcumstances (times of pollenating...), it will become the overpowering gene thus express itself as yellow color.
Reply:That is odd. Unless a graft has been performed, cross pollination can cause your "problem". Drought has a tendency to kill a rose, not change it genetically.
Reply:This has nothing to do with cross pollination. I believe what has happen is that the grafted yellow rose has died and what is growing is the rootstock that the yellow rose was grafted to. The rootstock of a rose is not a parent of the hybridize rose.
Reply:This sounds very strange to me,however i don't doubt your word.Perhaps they are hybrids and the old genetics are becoming dominant....Call your local extension office or consult your local library for a good book on rose genetics.
Reply:Sounds like it has been cross pollenating with a different race of roses.
Reply:cross-pollination
Reply:genetics
Reply:no the roses do change from year to years depends on the weather conditions and the bee pollination
Reply:It can possibly be from pollination from the bees. They may have gathered pollen from red/pink roses and pollinated your yellow roses afterwards.