For years hybridizers have tried to create the elusive, truly black rose. The idea was to be the first to develop this highly sought after flower, which would earn that fortunate person enough money to purchase a small island in the Pacific (something about the size of Australia). There is a dark-purple rose that some people (who may be slightly color blind) have called black; but, in reality, nothing even comes close.
That is until now! I discovered this rare rose recently, and I didn’t even have to do any weird hybridizing stuff. I simply walked out to the Rose Garden at the Ogden Botanical Gardens, and “poof”, there it was. In fact, just about every rose we have has turned into a black rose. Wait, we are talking about the stems being black aren’t we? What? You mean the color of the blossom is black? Never mind….
As all rose growers know, this is not the smartest plant in the landscape. Beautiful, yes, but pretty dumb on the plant intelligence scale (I think in rates about a minus 7). Most plants figure out when it is getting cold, begin dropping their leaves, and progress into dormancy about mid to late October. Roses, however, forget winter follows this cold spell, and continue growing and trying to look pretty until about January.
Most years, this is not a problem. But, when the temperature drops quickly from a nice growing temperature to well below freezing, like it did this past fall, the roses do not have enough time to acclimate. Plants need a slow cooling process of about two to six weeks to prepare for winter. They drop their leaves, move water and energy out of the stems and into the roots. As the water leaves the cells in the stems they harden, and are ready for cold temperatures. This explanation simplifies the process, but, basically, it’s too much cold too fast which equals dead roses.
When we get deep, freezing temperatures before the plant is ready, it compromises the integrity of the cells. This is similar to putting fresh strawberries in the freezer. They are nice and firm going in, but the freezing action of expanding water (ice) punctures the cell walls, and all the guts and important stuff leaks out. In other words, the strawberry dies just like our roses did.
Regardless, remove all the blackened canes which may include removing the whole rose. The good news in all this is we now have an opportunity to plant some of the cool new roses in our landscapes. I might recommend avoiding the black varieties…