I was intrigued to see a tree a few days ago with both pink and white blossom. How can this happen?

 

http://www.facebook.com/photo.php?pid=421796&l=1032f44911&id=1061329345

 

http://www.facebook.com/photo.php?pid=421790&l=a918c5d964&id=1061329345

One common way is grafting, which results in a chimaera (an individual whose somatic cells contain one of two different genomes).

Thank you. I can understand why they graft fruit trees, but I wonder why they would go to that trouble with a purely decorative tree in a churchyard? Is there any way this could happen without human intervention?

The tree could be monoecious, having both male and female flowers on the same tree.

There's a tree just like this in the street where my parents live. It's a graft, because you can see where the two trunks are intertwined. If you look closer, maybe you can tell if that is the case with this tree too.

Thank you both - I'll have a close look at the tree next time I'm there to see (a) if there's evidence of grafting, and (b) if the flowers are different sexes. (As you'll gather, I'm no botanist - physics was my line.)

It could be the result of the original rootstock throwing out a shoot. Cherry trees, particularly those planted in streets, are often grafted quite high. Sometimes the original rootstock can throw out a shoot just below the graft and that will result in the effect you see.

 

Another way this can happen is by a 'sport'. A tree can sometimes form a branch from a shoot that contains a minor mutation, giving the shoot some different property to the rest of the tree (usually in flowers, but sometimes in other ways). This is called a 'sport' and, if the difference is desirable, this can be the source of an entire new cultivar (cultivated variety).

 

The new cultivar is propagated by cuttings as any attempt to breed usually results in a reversion to type. This phenomenon is particularly common in Satsuki Azaleas. There are many thousands of satsuki cultivars and many are the results of propagating such sports, hence the amazing range of flowers and flowering habits in satsuki azaleas. It also accounts for the higher prevalence of sports in satsuki.

 

On some cultivars (e.g. 'Kaho' which usually has red and white striped and blotched flowers), a branch will form that will only put out flowers that are pure snow-white or solid red, in contrast to the rest of the tree. It can be quite striking to look at.

Thank you. I can understand why they graft fruit trees, but I wonder why they would go to that trouble with a purely decorative tree in a churchyard? Is there any way this could happen without human intervention?

 

Perhaps someone dd it deliberately to be decorative, though I think Glider's ideas are more likely.

Thank you Glider, that was most interesting. And thank you to John too - yes, I guess that's a possibility too.