How to Protect Rose Bushes for Winter in Canada

To protect rose bushes for winter in Canada, cut tender roses back, mound dry soil around their bases once the ground starts to freeze, and cover the mounds with mulch. How much protection you need depends on your hardiness zone and the type of rose.

The Canadian Rose Society says winter protection is needed in most regions, except for hardy shrub roses. Fall is the time to do it, and the steps below follow the society’s guidance, with additional mounding depths from the University of New Hampshire extension service.

Hybrid teas, floribundas, grandifloras and David Austin roses are the types most likely to suffer winter damage. Hardy shrub roses should not be cut back in fall, and the society says that for their first few years they need only soil mounded around the base.

Gather your materials before you start. You will need pruning shears, gloves, extra soil or a mix of soil and peat moss, mulch such as straw, leaves or wood chips, and, in colder zones, a collar to hold the mound in place. Bring in soil from elsewhere in the garden rather than raking it from around the plant, the university says.

Step 1: Wait for the plants to go dormant

Do not rush. The University of New Hampshire says to wait until hard frosts have killed the remaining leaves, and it suggests letting plants go through several nights in the mid-teens (Fahrenheit) so they are fully dormant before you cover them. Climbing roses should be protected after the first hard frost.

In the coldest parts of Canada, the Canadian Rose Society puts the work around Thanksgiving.

Step 2: Clean up the bed

Remove dead leaves and clippings from around each bush, along with any diseased or damaged stems. Dispose of them rather than composting diseased material.

Step 3: Prune the canes

The right height depends on your zone. In zones 2 to 4, the Canadian Rose Society says to cut tender roses to about 70 centimetres. In zones 5 and 6, cut canes to between 70 centimetres and one metre to limit wind whipping. In zones 7 to 9, cut to about one to 1.2 metres.

Climbers and large shrub roses in zones 5 to 9 can be left uncut. In zones 2 to 4, the society says to avoid cutting climbing canes if possible.

Make cuts just above an outward-pointing bud. Leave enough healthy cane to sit under the mulch, which the university puts at 18 to 24 inches (about 45 to 60 centimetres) for hybrid teas and floribundas.

Step 4: Mound soil around the base

In zones 2 to 4, wait until the ground is at least partly frozen. Place a collar around each bush and fill it with dry soil and peat moss to a depth of 40 to 50 centimetres. Water the bush well first.

In zones 5 and 6, build mounds 20 to 30 centimetres high around each bush. In zones 7 to 9, mound soil 20 to 30 centimetres up around the canes of tender varieties, using newspaper collars. The society says winter protection is usually unnecessary in coastal British Columbia.

Step 5: Add mulch over the mounds

Once the ground is frozen, cover the mounds with straw, wood chips, leaves or branches. The mulch keeps the soil frozen and helps prevent repeated freezing and thawing around the crown.

Step 6: Lay down tender climbers

If your climbing rose is tender, the society says to remove it from its support, lay it on the ground and peg it down. Cover it with up to 30 centimetres of dry peat moss. The University of New Hampshire offers a different method for climbers, which is to wrap them or cover the entire plant with earth.

Step 7: Protect new plantings

The society says all newly planted roses should get protection for their first one or two winters, even in the milder zones. Young plants have had less time to build up the root system that carries them through the cold.

Step 8: Uncover in spring

The Canadian Rose Society says to remove the winter protection in spring when the bush begins to leaf out. At that point, cut away any winter-killed wood and shape the bush if needed. Neither source gives a fixed calendar date, so watch the plant and your local weather instead.

Gardeners unsure of their zone can look it up on Natural Resources Canada’s plant hardiness map. Local rose societies and garden centres can also say which varieties do well in your area.

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Sources: Canadian Rose Society, Winter Protection; University of New Hampshire Extension, Winter Protection of Roses.