Sunday, October 27, 2013

Preparing a Rose Bed for Winter in Zones 4 and 5

It has been a disappointing year for the roses in the Gethsemane Prayer Garden. The 'Bonica' roses opened in mid-June as usual but the blossoms were not nearly as abundant as previous years. From the second week in July until the beginning of October, there were only a few buds on these normally gorgeous pink-flowered plants. The red 'Knockout' roses which are intermixed with the 'Bonica' in the center two beds were also fairly sparse. Only the yellow 'Knockout' roses in another flower bed were very prolific and wonderfully fragrant.


The difference I believe between the two pink and red rose beds and the yellow bed is the previous winter's treatment. In recent years I have not been protecting the roses from the winter elements, and last year the deer found the first two rose beds. The deer did not find the yellow bed of roses so they abundantly flourished. The deer first ate the leaves on the pink and red roses, and then progressed down the plants to where only 6" stubs were left.

Ten years ago when we first planted the roses, they were pruned in November to 12-18" and then heavily mulched so that only a few stems were visible. This worked well to keep out the deer, but in the third and fourth years, the voles (I thought they were moles but have since been corrected) girdled some of the plants. Also the plants did not reach their maximum potential size – the 'Bonica' roses were never taller than twenty-four inches tall.

On the advice of a local nursery, we stopped pruning and mulching the roses; they suggested that the shrub roses did not require the same finicky care that tea and floribunda roses demand. The damage from the voles was much less and the deer that regularly pass through the garden had for some reason stayed away. But not last winter!

Today I came across an article prepared by a member of the American Rose Society named Jack Falker. His blog entry http://jack-rosarian.blogspot.com/2013/09/voles-and-castor-oil.html offers hope that these tiny Pacman-style creatures will be brought under control while using traditional pruning and mulching techniques. He recommends a treatment of castor oil on the roses! I'll be giving that a try. (Jack also offers a blog article on winter protection: http://jack-rosarian.blogspot.com/2013/09/winter-protecting-your-roses.html.) Based on Jack's advice and my previous experience, we will cut the roses back to 12-18" when the first hard freeze arrives (usually in November) and then mound them with mulch.

There is some debate as to when to stop dead heading: some years we stopped in September and other years we stopped in late October. My sense is that if we are cutting the roses back to 12-18", then we can continue to optimize flower production; but if the drastic pruning was not part of our plans, we should have stopped our pruning much earlier so that the plant naturally prepares itself for winter.

This summer, rather than the normally prolific 'Bonica' and 'Knockout' roses, we had a vigorous production of "blind shoots." A blind shoot is a cane that produces lots of leaves but no flower buds – hence it is blind. I had been attributing the blind shoots to the very unusual weather patterns: sometimes very rainy and sometimes very hot. I also suspected that we may have over-fertilized the plants which released too much nitrogen. Possibly both of these reasons contributed, yet that does not explain why the yellow 'Knockout' roses were so vigorous.

I now suspect that the blind shoot problem had three contributing factors: the deer from last winter, the extra application of fertilizer to compensate for the severe damage, and the irregular weather. I pruned the canes in September that had no buds, finding the first branch with five leaves. Now we finally are getting some gorgeous flowers once again.

And Lord willing, we hope to have better results next year.