Do you think it could somehow be due to the extreme temperatures you have? My Rosa Mundi is 25 years old and has never had a flower that was only pink (OK, not that I noticed, anyway). The plant that I have is on its own root, FWIW.

I propagated RM from my grafted plant and the own root plant is reverting. I suspect it's just something that happens. We're USDA Zone 8.

My own Rosa Mundi came up entirely as Apothecary Rose this year. It was a small plant to begin with, and apparently I lost all of the original rose. Ah well, Apothecary Rose is a nice plant, too, though I did like Rosa Mundi quite a bit.

Rosefolly

My Rosa Mundi is currently about half and half. There's nothing wrong with the Apothecary Rose, except that I have one of those somewhere else, and not really enough room for two.

There's a very famous long hedge of Rosa Mundi in one of the stately gardens of England that is reverting to the Apothecary Rose in a major way, so I suspect it's a rather common occurrence. It must be annoying when it's one of the major features of a garden that's open to the public.

Ingrid

I think it was Graham Thomas who wrote that if it starts to revert you have to cut the pink part out to keep it true to Rosa Mundi. It sounds like this is rather common after all. Since I have Apothecary in another area, I'll mark the canes that have pink blooms and remove them when it's done blooming. We had a very mild winter, so I don't think temperature was the culprit. Thenk you everyone.

My understanding is that reversion (like the previous mutation that produced stripes) is a local phenomenon: a bud eye mutates back to the original, and everything growing from that point source will have the same reverted DNA. The rest of the plant is not affected. So if a whole hedge of Rosa Mundi appears to be reverting, it's just because the gardeners have not been careful to cut out the reverted canes when they appear. Each variety that began as a sport will produce reverted shoots at a certain rate depending on how stable the mutation was. For some, the rate is near zero; for others, you can expect a reverted shoot every few years.

Somewhat off topic, I see every day a variegated shrub that has a reverted all-green sector that seems to be rapidly taking over. The reason is that the all-green leaves are much more efficient at producing energy for growth. The reversion is not spreading to variegated shoots, but the reverted shoot is growing faster than the variegated parts and crowding them out. Something like that could happen with a climbing sport of a rose, but not with a floral color sport.

I'm sure that is what happened with mine. Rosa Mundi was struggling, almost growing backwards, in my garden. It's not really happy with my low-chill climate. I moved it to a different spot and it seems a bit better. But there wasn't much volume left to it, and if a critical bud eye mutated, the whole plant would revert.