I bought large climbing roses this summer, planted them in containers. They are finally growing, I originally was going to plant them in the ground this month, but now I am wondering what I need to do to keep them over the winter in the containers. Any ideas about cutting back, watering, keeping in a heated area?
I am assuming that you already know that your climbing rose is a type that does not have a good chance of making it out doors during winter – otherwise it would be best to leave it outdoors planted in the ground.
For all plants over wintered in a pot the situation is very stressful and often deadly. Roots are not adapted to endure the quick fluctuations of temperatures (from day to night, day to day, or Chinooks to winter again) that some above ground parts have. If the potted plants are dug into the ground before freeze up for the winter it helps.
When you say it is “finally growing” I wonder if you are talking about a stressed plant finally recovering, or a plant that was shutting down for winter that was stimulated with fertilizer to regrow? Both of these scenarios indicate a plant that will have a hard time getting through the winter – the first case does not enough energy reserves, while the later is using its reserves for new growth at a time when it should be shutting down.
Roses need to have a winter season. This does not mean all roses will survive the temperatures that Alaska has to offer or the length of time we have them, but they need a cool rest period. This may, ideally, be provided by a bright, cool location. This is not what is usually available in our homes. A garage that is constantly held in the 20’s to high 30 degree range will work. Even though it will probably be dark the plant will be dormant at these temperatures and not need light because the leaves are probably off anyway. The soil should be moist (not wet) to begin this storage period. Check once in awhile to see if a little water should be added to moisten the soil, but since the rose is at a very slow respiration rate in these cool temperatures, over watering can easily rot the roots. I am over simplifying a lot of this for brevity.
If you would like to enjoy the rose with any buds that it now has in the house, place it in a sunny location and water and feed it until it is done blooming and/or exhausted and then toss it into your compost bin. This is basically treating a perennial like an annual, which I how many people treat hybrid tea roses and other plants that can make it through some winters, but struggle the following year to put on much of a show.
Cutting back roses depends on what type of rose you have and what you plan to do with it. Hardy roses left outside over winter should not be pruned at all in the fall - with damaged and dead stems trimmed in spring. The rest depends on the size of the space you have to over winter. If you have lots of space for your roses, then leave them tall which retains more of the carbohydrates for over wintering energy and trim in the spring.
Oh, did I mention letting the roses experience several frosts to help it get the message to shut down, drop leaves, and move water in the proper places in the plants tissues before they are stored? This is a bit tricky too, because t frost too hard all at once is too much, too. Having the leaves drop off naturally is the idea, but you can also hand pick them off to keep things tidier and shut the plant down that way, also. Again, I am over simplifying and hope to give you the idea of what happens in a few words.
The Alaska Rose Society has been working on the Centennial Rose Garden most of this summer. I do not know if we will resume winter meetings, as we are still working on the garden chores through October – located near the west end of Delaney Park Strip in Anchorage.
President, Alaska Rose Society