Newfoundland Horticultural Society

A ROSE GROWER'S PRIMER – III

by Harry McGee ©National-Roses-Canada 2008    #3 of a series by Harry McGee

Roses: 1  3 &  5: Grown by Ian Senciall of the NHS,  Photographed by Ian Senciall and Joy Senciall

Roses  2  &  4:  Grown and photographed by Frank Smith of the ‘John Cabot Rose Soci of  N and L  and the ‘Newfoundland Horticultural Society’

 In the last two issues, we discussed (1) how to match the time you have available with the kinds of roses you choose to adopt, and (2) where to position them and how to give them a deluxe planting.

Now we will talk about winterizing the tender ones.

Ideally we shouldn't have to winterize roses, and to the extent we do, we are conceding that we do not have the right plant in the right place. However some of us are enslaved by high-centred tender roses and we have to pay a chilly price for this addiction. If you live in zone 1 or 2 [St. John’s, Newfoundland is in zone 5], or if your garden is in a very exposed area, you may want to follow this regime for your hardy roses too, just to make life a little easier for them. [David Austin’s English roses tend to lie between the tender and the hardy – so, for them, it’s safer to take the preceding advice.] On the other hand, if you garden on the really mild west coast [of Canada], you may not have to bother with any cover other than a few leaves swept up around the base of your plants.

Even if you live where the cold does not stop the rose bush from thriving, the sunlight reduction will shut down the leaf factories, and it's time to recognize that the growing season has ended.

You have stopped feeding your roses on the last day of July, and slowed down the watering, so that they have quit producing new growth. As the overnight frosts get sharper and the days grow short, they will stop blooming and their leaves will die and fall. The leaves on hardy roses will turn colours like the trees, and fall naturally, but the tender ones, having no sense of what is happening, will remain green and, if conditions are dry, they will be swept off by the wind. If you had a bad case of black spot, then you haven't had leaves for some time, and your roses have stored less food for winter survival.

After a few sharp frosts have visited your area, and the soil has begun to form a frozen crust, start to work. Prune your tender roses down to knee-high, about 20 inches (or 50 cm). [English roses should be included in the tender group for this purpose.] This is to prevent their long canes from thrashing against each other in the winter wind, cutting each other open, letting moisture out and disease in. Pruning also makes them less susceptible to wind rocking. In the case of miniatures, just reduce them by one third, making sure they are deadheaded (no spent blooms remaining). Do not cut back your hardy shrub roses (including antiques) and your climbers or ramblers. Shrubs will have their graceful arching shape spoiled by severe pruning and climbers that bloom on second year wood will be bereft of bloom next year. If you want to protect climbers, lay them bundled on the ground and cover after having put fresh rodent poison in a pipe under the enclosure.

Next, remove the leaves remaining on the tender rosebushes – especially if there is black spot on them. Rake up diseased leaves lying around on the ground. Garbage them - do not compost - the fungus spores will endure. Now make a little hill ten inches (25 cm) high around the base of the bush. Use well rotted cow manure, compost, peat moss, or earth from some other place. If you buy peat moss for this purpose, make sure you moisten it; otherwise the desiccated peat will draw moisture away from your roses. It is a job to moisten peat. Use a garden fork with a garden hose taped to its handle to turn it over while spraying it simultaneously. Rain will not do the trick. Only moisten it; do not make it soupy.

The reason for the little hill is to insulate the area of the rosebush near the graft, which you planted some inches below the surface. If the graft is exposed to cycles of freeze-thaw in the coldest months, it will weaken and the game will be over.

Don't rob the earth from around the plant as the roots are near the surface and shouldn't be exposed. The manure, compost and peat moss have the advantage of being suitable for spreading in the spring as mulch, which retains moisture and reduces weeds. Manure, of course, has the added benefit of being an excellent fertilizer. Peat moss may be hard to wet initially, but it is user friendly at removal time because it can be hosed away from the plant in the spring. Worked lightly into the soil, it will improve water retention. It will also bring alkaline soils closer to the ideal pH of 6.7. However, if the soil is already acid, [as is likely in Newfoundland] working it into the soil should be avoided. 

Leaves or straw are better than nothing for hilling, but they shelter mice and voles, which eat the bark all winter. They also rot by spring and become too wet around the plant. If you want to take those risks, then use oak leaves and wheat straw because they resist breaking down.

Those little hills must be removed in spring when the deciduous trees come into leaf. If you use materials that can be spread around, you can always gather it back if an untimely frost is forecast.

There are a lot of other materials you can use for winter protection - anything from evergreen branches to washed seaweed, from woodchips to carpet, from burlap to moss, from garden fodder to grass. Materials likely to be blown away must be anchored with wire netting or retained in collars. Beware of plastic, which holds heat from the winter sun, and water from snow melt. Sophisticated rosarians may use specially made poly-foam sheeting to insulate whole rectangular rose-beds, but it is a special drill, hard to locate, an expensive capital outlay, and a problem to store. Some have substituted tarp instead. It is also dicey as to when to remove it in spring because roses come into leaf under it before the last killing frosts are gone.

It goes without saying that the best winter insulation is deep snow. Trouble is that its presence is unpredictable. None may fall on the Pacific coast or on the tundra or desert (Palliser Triangle), or what falls may disappear with the next Chinook, or may be on-again off-again with monthly thaws as air masses alternate between Alaskan and Caribbean outflows. Even high average snowfall cannot be relied on to be continuous. So the best insurance is covering. It's just part of the Canadian condition - like overcoats and ski jackets.

If you have standard (tree-form) roses, or container roses, leaf-fall is the time to bury them. I prefer to take no chances and bury them sideways in a well-drained spot at least a foot (30 cm) deep until the trees come into leaf again.

If you rebel at the idea of grooming and protecting roses and doing all that labour in the autumn chill, then get hardy roses - the Canadian Explorer Series or the Parkland Series, or the hardy roses developed by the early Prairie hybridizers. Some antique roses are also eligible - mainly the oldest gallicas, damasks, albas, and centifolias. These roses and our wild roses can take care of themselves very nicely without any pampering to survive our Canadian winters. And most of them are hung with cheerfully coloured hips that can be floodlit to chase away long winter nights.

By permission of the author  .   .   .  HM