The Northern Plains states are already experiencing cold weather and a good portion of the rest of the northern part of the country has also, or is about to. Here in the upstate of South Carolina we are going to flirt with our first frost later in the week and the mountains are sure to get one.
This is the time of year we welcome a slight frost to shut our roses down but fear a sudden hard freeze. The latter could inflict damage not only on roses, but on many other plants as well. Unless it’s a really nasty freeze your roses will bounce back from any potential damage, so no need to suddenly build a greenhouse over your garden or take extreme measures. What is important is to understand not all freezes are created equal.
The variable is the wind.
My experience in gardening in a climate like ours over the last 14 years, is that temperatures in the low 20s and teens without wind can cause slight damage. However, if you couple those temperatures with strong winds the damage can be severe.
Think of going outside in the winter with exposed skin; even on your hands. If it’s cold yes it’s uncomfortable, but think of going outside when it’s cold and the wind is blowing. That cold wind just cuts through you and for our purposes it also sucks the moisture right out of your skin. That’s why your hands, face and lips feel chapped.
The same thing happens to your roses. The cold wind blowing across the plants pulls the moisture right out of them and dries them out. I’ve seen from personal experience more damage caused by cold wind than cold temperature. I’ve seen temperatures in the teens with no wind have little affect. However, I’ve seen temperatures in the low 20s with winds cause damage. Particularly this time of year and in late winter/early spring when the roses are still actively growing. When the roses are truly dormant there is little affect.
So, what can we do if the forecast calls for a freeze with high winds while the roses are still vulnerable? Our local weatherperson always says to cover our delicate plants when the forecast calls for those conditions. That may work for a few pots on the porch or late vegetables but covering all your roses likely isn’t doable.
When I had my rose nursery we used to take a trick from the citrus farmers in north Florida. We would overhead water the roses as the temperatures dropped to coat them with a layer of ice. No matter what the temperature is outside, underneath that ice it’s just at freezing. Furthermore, the ice acts as a wind barrier. We would also make sure the roses were well hydrated by watering them before the temperatures dropped below freezing.
I wouldn’t worry about this if the winds forecast are under 20 MPH. However, if they are forecast above that with temperatures in the very low 20s or below try it at this time of year. If it’s a freeze with no winds I wouldn’t worry about it. You only really need to think about this if these conditions are forecast during your first couple of freezes. After the roses have been through a couple of freezes they will quickly go dormant and none of this will be an issue. So, don’t do all winter long or you may get odd looks from your neighbors. Not to mention some interesting ice sculptures!