A garden without roses is, well, it just isn't quite complete. But many gardeners shy away from this best loved of all the flowering plants because of that dreaded gardening season: Winter.
True, winter in any part of the country is erratic at best and many roses do require some protection from the extremes, but successful overwintering is not only possible but virtually assured when done on a timely basis.
Winter Kill
Note: Though this article is written specifically for those living in USDA Zone 5, the general guidelines apply to all parts of the country where winter is a factor in plant survivability.
Winter kill is caused by extreme cold temperatures greater than a plant can tolerate. It manifests itself in cane or bud dieback, graft dieback and sometimes, overwhelming root kill. Winter kill susceptibility is often genetic, that is, a specific species or variety is not and never will, be able to survive a winter.
General Guidelines
The Basics
Don't fertilize your roses after August 15. The new growth will likely not sufficiently 'harden off' in time. When the season is over, after two or three hard freezes, usually late October, cut back any long canes to reduce wind whip. Remove just enough to bring the plant into balance.
After pruning it's a good idea to spray the canes with an antidessicant such as Wilt-Pruf(reg) to minimize moisture loss from winter winds. An application usually lasts about 6 weeks.
Once the soil is frozen, sometimes well after Thanksgiving in Zone 5, apply a layer of organic mulch 8" to 10" deep over the crown of your roses. The purpose of this protection is not to keep the plants warm, (You'll never accomplish that!) but to keep the ground frozen.
Alternating cycles of freezing and thawing causes plant to heave, breaking roots, often completely exposing them to the drying brunt of winter.
Mulching & Covering
Snow is the best winter mulch but not too reliable. Garden soil, mushroom compost, cypress or cedar bark, shredded hardwood, pine needles, and straw all work well.
Styrofoam rose cones are fine but don't cover your roses until early winter. If needed, tie the rose canes together for a snug fit. The main problem with these types of covers is it can really heat up under there on sunny winter days. So if we get into a 'January thaw' period be ready to ventilate.
Don't de-mulch (Is that a word?) or uncover your roses until the spring thaw is in full swing. Roses break bud very early in the spring and the tender new growth is often blackened by March & April cold snaps. Such damage usually doesn't kill the plant, but it can set it back.
After leaf fall, when the plants are dormant, remove all fallen leaves and spent roses.
Meticulous fall clean-up will reduce the overwintering spores of various fungal diseases.
A Few Specifics
Miniature Roses
These are usually on their own roots, not grafted, and are inherently hardier. While they don't require the above protection it certainly won't hurt them and will provide a big degree of comfort when record setting low temperatures plunge toward us unpredictably.
Hybrid Tea, Floribunda, & Grandiflora Roses
To protect or not to protect? It seems that no matter what you do you'll lose a portion of these grafted types every year. If you decide that you want to give them the best possible chance, use whatever above method is most convenient for you.
Climbing Roses
Most commonly available varieties are very hardy in Zone 5. Prune only dead or broken canes; removing healthy wood will eliminate many of next year's flowers. If you're really concerned about your climbers and like to wrestle with plants with thorns, here's two old time methods of protecting them.
Tree Roses
If you don't protect a Tree Rose during Midwestern winter it will die. Simple as that. The graft, the most vulnerable part of the plant, cannot be left exposed to winter weather. Hopefully you left your tree rose in a container. If so, overwintering is a snap. Just move the pot into shed or an unheated garage and check it for water once a month or so. (Plants do dry out in the winter.)
If you planted your Tree Rose here's what you need to do. With a sharp spade cut the roots around half the plant. Lay it over into a trench and completely cover (bury) it with 6" of soil.
Not enough room in your bed to do that? Then it's time to make another sculpture (See Climbing Roses above.) Drive a secure stake in the soil next to the rose. Tie the plant to it. This is to keep it from bending and cracking during gales. Next build a cage out of chicken wire around the rose. Fill the cage with straw. Then wrap burlap around the cage and secure with strong twine.
Rugosa Roses
This class needs no protection whatsoever. Seriously. They are extremely hardy roses, surviving even into the Hudson Bay region of Canada.
Heirloom, Modern Shrub, English, Romantica, Buck, Towne & Country , New Generation Roses and National Parks
All these types and varieties are very hardy at least into Zone 5 and require no specific winter protection. If you're still a bit leery, it won't hurt to protect them, especially the first winter after planting. After all, who knows how severe the winter will be? Cut back any long, lanky canes and mulch as you would a Hybrid Tea.
Tom Schneider is a horticulturist, avid gardener and retired arborist. When not enjoying his Midwestern garden he is assisting his wife, Deb, with their business, Windstar Embroidery.
Visit Tom and Deb for embroidered linens and gifts and machine embroidery designs.