Fall & Winter Care for Roses in the Extremes

Winterizing Roses in the Extremes

Roses are tougher than you may think. I have had great success with over-wintering many roses that are rated Zone 4, 5 or 6 in my Zone 3A garden. In addition to Zone 3A, which basically means that it is common to dip to – 40ºC or F. Of course there are other factors that determine the Zone, which may include altitude (1084m or 3556 ft for Calgary) and typical weather systems. Calgary is located in the Chinook belt; therefore during the winter the huge temperature swings are very hard on the plant material.

For a number of years I have been growing Hybrid Teas, Floribundas, miniatures and of course hardy shrubs. Mid October to Mid November is the time to put the roses to bed for the winter.

• All (hardy and not-so-hardy) need to be watered in the fall. This is the most important do or die task.
• No rose will make it thru the winter (Zone 3A) in a pot. They have to be planted into the ground. I transplant all my container roses into the veggie garden for the winter. Typically the ground does not freeze here until Mid November, so about a month before ground freeze is a good guideline for transplanting roses.
• Once there have been several frosts and most of the foliage has dropped, it is time to mulch. If the night temperature become consistently colder than -10ºC or 14ºF, it is the time to add protection.
• I have tried different mulches for winter protection and find peat moss the best. It seems more insulating than straw or leaves. It also forms a hard crust, so it doesn’t disappear over the winter and you don’t need to use the rose huts. Peat moss is also dual purpose because in the spring I spread out the peat moss in the flowerbeds and work it in which is a great amendment to the existing soil. With straw and leaves it can be quite a job for spring cleanup.
• Once the roses are ready for mulch, the peat moss is applied. I try to bury the minis completely and mound about a foot high on all the other not-so-hardy to the area roses. The canes can be cut down to about 2 feet so they do not whip in the wind and break. Wet the surface of the peat moss mound and it will form a hard crust and not blow away.
• The hardy roses do not get any special treatment other than a good fall watering.
• All canes below the peat moss level will remain green throughout the winter.
• Spring uncovering is one of the most important steps of successful over-wintering the roses that are pushing the zone. Once the night low temperatures start to consistently become warmer than -10ºC or 14ºF, it’s time to start removing the peat moss. Do this a little at a time, so it will be 3 to 4 weeks to have the mulch removed. Peat moss heats up a lot with the daytime heating and you don’t want the rose to start to bud out too much, too soon. By removing the mulch in stages, it will send out new shoots that are able to withstand those spring frosts in May. The uncovering typically begins in early April, but it depends on the weather. I usually trim off the winter kill or shape the roses at the end of April.

This is what I do, hope it helps

All good information, Joanne.

Ya know, if we moved somewhere warmer (like, almost anywhere else) we wouldn't have to go through all that trouble, Jo. Winter sucks. Winter in October really sucks.

Feeling sour,
Jo North

Have 2 more to move into the veggie garden. I will mound the peat moss in a few weeks.

Hey, that looks just as crammed as my garden does now. There is NO way that I'm doing this next year. I planted 12 regular-sized tender roses and 12 mini-roses in a teeny tiny garden space in my back yard. I'm sure they'll survive - they're so piled on top of each other they'll keep each other warm. I'll do the peat moss thing in a while too.

Got everything in, including the alpine & everbearing strawberries from the strawberry pots. I forgot about some tulips, so they will go in between the roses and will transplant them into somewhere in the spring.

Next step is the peat moss mulch.

Thanks Joanna. As you'll see I don't live in Canada, but it gets below -30 Celsius here. I moved from the balmy SW of England three years ago, and I'm on a steep learrning curve!

Roses & Snowcover
Here's a bit more info on roses and snow cover (we normally do not have snow cover throughout the winter, but last year we did. I wrote this last year and all the roses were great this summer.)

I thought I would share an observation regarding snow-cover. "Snow is a good insulator". Anyone who gardens in the North, probably heard this numerous times and even repeated the statement to others, without knowing how much of a difference the snow makes. I had put a remote temperature sensor from Home Depot, in a flower-bed last fall. It has become our favorite gauge of the temperature outside, since the digital display is on the base unit in the house. It is a very accurate ambient temperature sensor and proved to be more believable than the big thermometer hanging off the garage outside west facing wall.

We had some lovely mild temperatures into December. I remember seeing a fly in the yard on Dec 1st, which I thought was very odd for Calgary. Our first snowfall in December was accompanied with mild temperatures. That dump of snow provided a very good insulating blanket for the big dip into the -30ºC (-22ºF) from 0ºC or 32ºF. The remote sensor was placed about 1 cm or 3 inches above ground level with the moisture probe in ground. I didn't realize how much of a difference the snow cover makes. Very interesting. With 2.4 cm or 6 inches of snow cover and an ambient temperature of -30ºC or -22ºF, the remote registered -8ºC or 18ºF. With temperatures around -20ºC or -4ºF, the remote sensor registered -5C or 23ºF. In addition to snow insulating from the cold ambient air, the warm Chinooks were also affected. At +5ºC or 41ºF ambient, under the snow it was still -2ºC or 28ºF. Wow, what a difference. My not-so-hardy roses may survive this winter very well with the blanket of snow. (Which they did and Austin Gertrude Jekyll grew to over 3 m or 9 feet the summer of 2009)

There are a number of remote weather devices available on the market. A couple of things to consider when shopping for one are: lithium batteries work better in extreme cold temperatures for the sensors; check the lowest temperature the device will register. The Lee Valley Tools unit specification states the unit will register low temperatures to -39.5ºC or 39ºF. There are some units that are only good for -20ºC or 4ºF, so do check. Additional remote sensors are available with the Lee Valley Tool unit. Other retailers sell the base unit with one remote and do not offer extra remotes. We have 3 remotes with the Lee Valley unit (inside the garage, backyard and front yard). A click of a button and I can check all 3 locations. The Home Depot unit has a moisture probe and adjustable alarms for low and high temperatures (nice for inside a greenhouse). The base unit displays the temperatures, moisture level and low battery indication for the remote. Very cool gardening toy.

I certainly will be more diligent on shoveling the snow on the flower-beds in the future. It not only provides future moisture, the insulating value is huge. The roses will have a fighting chance this year if the snow cover stays.
Some official info: http://atlas.nrcan.gc.ca/site/english/maps/environment/climate/snowcover/1

This message was edited Nov 3, 2009 7:44 PM

Thank goodness I managed to get the roses mounded 2 weeks ago, while the temperatures were still quite warm, since we had a big snow storm and the temperature dropped big time. I like to wait until the night temps are consistently -10ºC or 14ºF before I mound peat moss...less likely to get the little critters munching on the roses.

Although it is very sunny, it is extremely cold out.

Currently -18ºC or 0ºF
Windchill: -30ºC or -22ºF
Low tonight of -27ºC or -17ºF

Here a picture, taken today, of all the roses in the veggie garden.

Well, Joanne, at least they are well insulated now...

Yes, the roses are well insulated now with all that snow.