Rose Care For Winter

Roses can be broken into two categories; Shrub roses and Hybrid Tea roses. Shrub rose does not mean that it is hardy; these roses are usually hybridized from a cross between hybrid roses and wild roses. Hybrid Tea roses are either budded or grafted meaning they are not growing off of their own rootstock. We will class floribunda, miniature, grandiflora, English, and romantica roses as Hybrid Tea roses for winter care instructions.

Shrub roses

Some plants will experience some die back from the tips of their canes otherwise some will die back to the ground after winter. These plants are considered crown hardy and will not need to be protected. They will grow either from the ground or from where their last bud was the next spring.

There are some shrub roses than need some winter protection, a rose cone works well. I would suggest covering any shrub rose at the base of the plant for the first couple of years to ensure survival as it roots in. The following are examples of shrub rose types and how they will experience winter here in Minnesota.

Explorer Series: Named after famous Canadian Explorers. Many are very hardy if not just crown hardy they may die back and come from the ground every year.

Meidiland: Most should have winter protection and the bud graft should be planted 4 in. below ground to increase hardiness.

Morden or Parkland series: Grown from their own rootstock and there is no problem if they die back to the ground and come up next spring. Early winter protection is best for young plants.

Hybrid roses

Why do we cover?

Winter protection is essential for Minnesota. It must serve two functions: (1) To keep temperature high enough to prevent winter kill and (2) low enough to keep the roses dormant and prevent active growth. Covering also serves to keep the sun and wind off the bushes. The sun and wind during the colder months can dry and wither the canes, a common cause of winter damage.

A good starting date would be about October 20th, and certainly before the temperature threatens to reach 20 degrees Fahrenheit. A drop below that temperature would kill or severely damage unprotected roses.

1. Water generously to keep the soil in good, moist condition.
2. Give your plants a good dormant spray. Some of the popular sprays for this purpose are Phaltan, Mildew King, and liquid lime-sulphur.
3. Tie the canes of the bushes together to make them easier to handle.
4. PRUNING: Most growers avoid fall pruning, because the open wounds on the canes may not heal properly. Cold weather may prevent the formation of a protective callus.
5. Dig a hole, starting away from and working toward the base of the bush. Dig the trench as long as the bush is high. Dig it wide enough and deep enough to accommodate the bush or bushes. (You can put more than one bush in a good-sized trench.) Pull the soil away from the shank (the root stock just below the bud union or graft – see figure below). Dig carefully so as not to damage the bush or its roots. Use a spade or shovel for the trench. Use a spading fork in loosening the soil around the roots.
6. When the trench is ready and the roots of the bush are loosened, use a spading fork to push the bush into the trench. (See figure below) Use the spading fork (or wire loops or weights) to hold the bush down while you cover it with 2 or 3 inches of soil. If the soil you removed in digging the trenches is not enough, add soil from your annual garden or elsewhere. REMEMBER: In the tipping method, only the roots bend. Pull the soil away from the shank, and it will be easy for the roots to bend.
7. Cover the soil with about 1to 2 feet of loose leaves or other covering such as marsh hay.
8. Place several little tins of rodent bait among the leaves to discourage the visits of small (but destructive) field animals.
9. Water the leaves well. The water cuts down on the danger of fire and also formed ice crystals to help the plants stay in a dormant state. Use fencing (chicken wire is good) around the rose bed (or lay it on top of the leaves) to keep leaves from blowing in a strong wind.

Other ways to protect tender roses in Minnesota

HILL AND COVER (Follow steps 1-3 from above)

1. Mound up the base of each bush with soil – about 9-12 inches. A wire cylinder may be used to hold the soil in place. Very tall canes, which would whip too much in strong winds, may be cut back and the cane ends sealed.

2. Cover entire bed with a bout 2 feet of leaves or hay, held in place by a fencing. Water.

3. In the spring, gradually remove the leaf cover, starting around April 1. Then gently wash the soil off the bushes in stages, beginning around April 10-15. If additional soil was brought in to mound in the fall, be sure to remove the excess soil.

POLYSTYRENE CONES (Follow steps 1-3 from above)

1. Prune back the bush to accommodate the cone. Then place the cone over the bush and tightly seal the bottom of the cone with soil. Weight the base of the cone down with more soil, gravel, stone or some other weight material.

2. The cones with detachable tops (for ventilation) are best; with these on warm days in late winter, the rose bushes can and should be given some air. The cones get like a miniature greenhouse with the warmth of the early spring sun. Mold can be a very serious, severe problem then; if unchecked it can cause death of the canes.

3. In the early spring, remove the cones when temperature gets above freezing. Keep them handy to put back as necessary, for the plants will be very tender and sensitive to sun and drying winds in addition to the cold.