Perennials & Shrubs

Getting roses through a Minnesota winter

The short answer: hardy shrub roses mostly take care of themselves. Stop feeding them in summer, keep watering until the ground freezes, mound some soil over the base after a few hard frosts, and leave the pruning for spring. Most rose losses in Minnesota aren't from the cold itself. They come from soft new growth that went into winter unready, from roots that dried out, or from freeze-and-thaw cycles in March.

First, know which kind you have

• Hardy shrub roses on their own roots: Oso Easy, At Last, the Canadian Explorer roses like John Davis and William Baffin, the Parkland roses like Morden Blush, and rugosas. These are rated to zone 4 or colder, and even if the tops die back they regrow true from the roots. This guide is mostly about them.
• Tender roses: hybrid teas, most floribundas and grandifloras, and anything grafted (look for a knobby swelling just above the roots). These are not reliably hardy in Minnesota. They need heavy protection, or the “Minnesota Tip” method, where the whole plant is laid down in a trench and buried. Ask us if you have one of these and want the details.
• Patio and mini roses bought in pots for the season are usually treated as annuals here.

Late summer: let them slow down

• Stop fertilizing by August 1. Fertilizer in late summer pushes soft new canes that don't have time to harden before the first hard freeze.
• Stop deadheading in early September. Letting the last flowers form hips tells the plant the season is over.
• Keep watering through fall whenever we go a week without about an inch of rain. A rose that goes into winter with dry roots is the one that comes out dead. Our fall watering guide has the details.

After a few hard freezes: mound the base

Once you've had several nights in the low 20s, usually early to mid November around East Bethel, pile 8–12″ of soil or compost over the base of each plant. Bring the soil in from somewhere else; don't scrape it up from around the rose, which exposes the roots you're trying to protect.

The mound isn't there to keep the rose warm. It keeps the crown and the lowest buds at a steady temperature through the freeze-thaw swings of late winter, so even if every cane above it dies, the plant regrows from the protected buds. After the ground freezes you can add a layer of shredded leaves or straw on top.

What not to do in fall

• Don't prune. Cut canes freeze back past the cut, so a fall trim just means losing more. The only exception is a cane that's broken or whipping around in the wind; shorten that one.
• Don't wrap roses in plastic or use foam rose cones on hardy shrub roses. They trap heat on sunny winter days, and the plant starts to wake up too early.
• Don't mulch too early. Mulch on unfrozen ground makes a cozy winter home for voles, who will happily eat the canes.

Rabbits

Rabbits do more winter damage to roses in the metro than cold does. Once the snow gets deep they can reach higher, and they'll chew canes right down to the mound. A cylinder of chicken wire or hardware cloth around each plant, a few inches taller than your usual snow depth, solves it. Our new shrubs guide shows how.

Spring: uncover slowly, then prune

In April, once the ground has thawed, pull the mound away over a week or two instead of all at once. When the buds start to swell, usually mid to late April, cut out anything dead or blackened back to green wood. On most hardy shrub roses that's all the pruning they need. The ones that died to the ground over a hard winter will come back from the roots and still bloom that summer, because shrub roses bloom on new growth.

Common questions

Do I need to cover my roses for winter in Minnesota?

Hardy shrub roses such as Oso Easy, At Last and the Canadian Explorer and Parkland roses rarely need more than a mound of soil or compost over the base after a few hard freezes, usually early to mid November. Hybrid teas, floribundas and grafted roses are tender here and need much more protection.

Should I prune roses in the fall?

No. Fall pruning invites dieback because the cut canes freeze back even further. Leave the canes alone in fall, except for anything broken, and do the real pruning in spring once the buds start to swell, usually mid to late April.

When do I take the winter mound off my roses?

In April, once the worst cold is past and the ground has thawed. Pull the mound away gradually over a week or two rather than all at once, then cut out any dead or blackened canes back to green wood.