Getting Roses Through a Northern Winter: Sort Them, Wait, Then Cover

The first hard frost has blackened the tomatoes, and your hybrid tea still has a couple of buds on it. Now you're wondering whether to cover it before Halloween or wait. Wait. Most rose loss up north comes from protecting the wrong plants at the wrong time. Hardy shrub roses can ride out winter uncovered. Hybrid teas, floribundas, grandifloras and English roses need protection, but only after they go fully dormant. Below I'll go through which roses need cover, when to start, how to mound or tip them, and when to uncover them in spring.

The short answer: sort your roses, then wait for dormancy

Start by sorting what's in the bed. Chicago Botanic Garden says shrub roses generally need no extra winter protection beyond some shaping. NDSU Extension says the same about hardy, disease-resistant shrub roses such as the Canadian Artist Series. Leave those alone.

The roses that need protection are the tender ones: hybrid teas, floribundas, grandifloras and English roses. These are the plants you lose when a January thaw is followed by a hard freeze, or when a dry, bitter cold settles in with no snow on the ground.

Timing is where most people go wrong. NDSU and Chicago Botanic Garden both say to wait until the rose is fully dormant, after several hard freezes. Chicago Botanic Garden gives a practical cue: winterize hybrid teas and English roses after several days in the teens. If that cold hasn't come by Thanksgiving, do the job anyway.

We think about timing the same way on a golf course. Covers and dormant treatments go on when the turf has shut down, not when the calendar says it's fall. If you cover a rose too early, you're keeping a plant warm that's still trying to grow.

Late-summer and fall prep

You get a rose ready for winter starting in August. The goal is to stop pushing soft new growth so the plant can harden off.

• Stop fertilizing in early August. Chicago Botanic Garden says early August. Missouri Botanical Garden says around August 1 and also suggests cutting back on watering. New shoots that come out in September are the first thing winter kills.
• Stop deadheading. Chicago Botanic Garden says to stop by Labor Day. Missouri Botanical Garden says to let hips form in October and remove only the spent petals. When hips are forming, the plant takes it as a signal that the season is ending.
• Clean up the leaves. NDSU and Missouri Botanical Garden both recommend removing fallen leaves and debris from around the plants, because dead rose leaves can carry fungal spores into next year. Raking out a rose bed takes about ten minutes, and it's the cheapest disease control you'll ever do.
• **Don't prune hard in fall.** Chicago Botanic Garden warns that fall cuts won't callus before winter. You will see advice to shorten tall canes so they fit under protection, and that's covered below. Taking a rose down to a few stubs in October is a different thing, and you shouldn't do it.

Method 1: Mounding

Most homeowners with tender roses should mound. The point of the mound isn't really to keep the plant warm. Chicago Botanic Garden explains that mounding keeps the base of the plant uniformly cold, which cuts down on damage from repeated freezing and thawing.

When: After those several hard freezes. Missouri Botanical Garden gives a two-step schedule. Do a first trim after the first hard frost (28°F or lower), then mound after the second hard freeze (20°F or lower), which there usually comes around December 1. In colder areas this happens earlier.

Trim to fit first. Missouri Botanical Garden cuts hybrid teas and grandifloras to about 3 feet and floribundas to 18 to 24 inches. Chicago Botanic Garden cuts hybrid teas and English roses to knee height. This is only to make the plant fit under the protection. It isn't spring pruning.

How deep: The sources disagree here, so treat these numbers as a range and pick based on your climate:

• 6 to 8 inches, packed firmly (Missouri Botanical Garden)
• 8 to 10 inches (Chicago Botanic Garden), or 12 inches of composted manure or light soil over cut-back hybrid teas
• 10 to 12 inches of well-drained compost (NDSU)

If you live farther north, go deeper.

What to use: Use soil, compost, decomposed manure or shredded bark. Bring it in from somewhere else. Don't dig it from around the rose, or you'll expose the roots you're trying to protect. The sources split on leaves. Missouri Botanical Garden says leaves and grass clippings are poor material for the mound itself. Chicago Botanic Garden and NDSU both put shredded leaves or straw over the mound. My read is that the mound core should be soil or compost, and leaves belong on top as an outer layer.

Holding it in place: NDSU waits until the mound is firmly frozen, then adds another foot of leaves or straw held in a chicken-wire cage. Chicago Botanic Garden also uses chicken-wire cages to hold shredded leaves over the canes. A circle of wire with a couple of stakes keeps everything from blowing into the neighbor's yard.

Skip the foam cones. NDSU no longer recommends Styrofoam rose cones. They trap moisture that can cause rot, heat up on sunny winter days and break dormancy, and blow away if they aren't secured. Missouri Botanical Garden still lists cones as an alternative. I'd go with the mound.

Method 2: The Minnesota tip

If you're in the coldest areas, or you're growing tender roses you can't stand to lose, the Minnesota tip gives more protection than a mound. You partly lift the plant, lay the whole thing on its side in a trench, and bury it, canes included. NDSU lays out the steps:

1. Bundle the canes. Tie them into a tight bundle with soft fabric, then apply a fungicide.
2. Dig a trench next to the plant that's as long, wide and deep as the plant needs to lie down in it.
3. Loosen the roots on the side opposite the trench with a spading fork.
4. Tip the plant into the trench. Pull soil away from the crown so only the roots bend, not the canes or the graft area.
5. Backfill to cover the plant.
6. After the soil freezes, add another foot of leaves or straw on top.

The University of Minnesota Landscape Arboretum does this every year to the more than 450 roses in its Wilson Rose Garden. It spreads the work over two weekends in mid- to late October, with tying on one weekend and tipping the next. In 2024 it tied on October 26 and tipped on November 4. Those were that year's dates, not a rule. Watch your own weather.

The Arboretum crew uses a few tricks worth copying:

• Leave a long tail of twine on the bundle. You use it to lower the plant into the trench, and in spring it tells you exactly where the rose is buried.
• Tip each rose in the same direction every year, so the roots get used to bending one way.
• Water after covering, then add straw mulch once the ground freezes.

It's real work, about an hour of digging per plant. Tipping is meant for the roses you'd hate to lose. You don't need to do it to every plant in the bed.

Spring uncovering and pruning

Uncovering too early can hurt the plant as much as covering too early. There's no single date for this. Chicago Botanic Garden says to start pulling protection in late March or early April, when new growth starts, and to be careful not to break the new shoots. Missouri Botanical Garden is more cautious and says to wait until all danger of frost has passed. Up north, I'd take that as a reason not to rush. You can pull back the outer straw or leaves first and leave the soil mound in place for a while. I'm suggesting that as a judgment call. It isn't from any of the sources. For tipped roses, the Arboretum just says the process "is reversed" once the weather warms: dig out the plant, stand it back up and refill the trench.

Prune once the protection is off. Iowa State Extension puts that window at late March to mid-April. Before you cut anything, check each cane:

• Live wood: green bark, plump buds and a white pith (the center of the cane) when cut
• Dead wood: brown bark with a brown or gray pith

Iowa State says to remove any cane with no life in it all the way to the base. On the canes that survived, make slanted cuts about 1/4 inch above an outward-facing bud, so new growth goes outward and the center of the plant stays open to air. Moving air dries the foliage, which helps it fight disease, and that's the same thing we do with fairways.

How far to cut depends on the winter. After a mild winter with little damage, Iowa State says to cut canes back to 8 to 12 inches above the ground. After a hard winter, cut at least 1 inch below any brown, dead area. You keep whatever is alive, even if that's not much.

Skip the problem: pick hardy roses

The lowest-maintenance way to deal with all this is to plant roses that don't need it. NDSU recommends winter-hardy, disease-resistant shrub roses such as the Canadian Artist Series, naming 'Campfire' and 'Emily Carr', as roses that need no winter protection. Chicago Botanic Garden says the same about shrub roses in general. That's the same approach we take on a course. We put the right plant in the right spot so the crew isn't fixing it every season. If you're tired of mounding and digging every November, you can replace a tender rose with a hardy shrub rose when you get the chance.

Sources (5)

• NDSU Extension, Dakota Gardener: Winter protection for tender roses
• Chicago Botanic Garden: Winterizing roses
• Missouri Botanical Garden: How do I winterize my roses?
• University of Minnesota Landscape Arboretum: Rose tipping in the Wilson Rose Garden
• Iowa State University Extension: How should I prune hybrid tea roses in spring?

Photo: Rose & snow by Martyn Wright, BY 2.0.