Process can be difficult, but necessary to save rose bushes

By Bev Johnson

Master Gardener

Roses are a diverse group of plants that have many options for gardens here in the frozen north. Some shrub rose cultivars are completely hardy or have very little dieback in zones 3 and 4. Remember we are in 4B but it is usually a good idea to get zone 3 plants here in the middle of the state.

You can usually just mulch around the base of shrub roses as you do with all your perennials, and they will come though the winter in good shape. However, most roses sold in Minnesota are sissies and need blankets and quilts and comforters to get through our winters. These include the tea roses, floribundas, grandifloras, miniatures, climbers and some shrub rose cultivars. They are often considered annuals here but if you are determined enough, you can overwinter them.

Start by discouraging succulent late season growth by; limiting fertilization, especially nitrogen after August 1st. Don’t prune heavily in late summer or fall and keep deadheading till freeze up.  Keep watering being careful not to let the leaves go into the night wet.

The goal of winter protection isn’t to keep the frost out but to keep it in and prevent cycles of freezing and thawing and the temps from dropping far below freezing. Do not use Styrofoam cones for this. They cause more harm than good. As the late winter sun beats on them, the temperatures can get as high as 80 degrees inside them then drop below freezing when the sun goes down. Result: one cooked, dead rose.

There are two major ways used in Minnesota to successfully protect tender roses growing in the ground. One is the Minnesota tip method and the other by mounding insulation around the plant. This article will discuss the Minnesota tip method

Albert Nelson came up with the tip method in the 1950s. He had been growing roses since 1920. He took information learned from protecting raspberries in the Northeastern states and experimented with his roses. The suggestion was to mound soil around the base of the berries and then bending down the canes and covering them with different types of mulch usually in mid to late October. This is what he came up with.

Spray the roses with fungicide and water the soil a day or so before tipping. Tie the canes together from the bottom up to reduce the size. Use synthetic string or twine that won’t degrade in wet soil. Now dig a trench as long as the plant is tall, about a foot deep or more depending on the size of the rose. Loosen the root mass of the rose on the opposite side of the plant. Carefully tip the rose into the trench. You may have to loosen the root system with a garden fork to accomplish this. Next, pressing the rose into the trench, backfill and mound soil over the canes being sure to cover all of the rose. Top with a couple of feet of mulch. It’s a good idea to mark each end of the trench so you don’t inadvertently start digging in the middle of the plant in the spring since you should have mulched all the flowerbeds with 2 feet of mulch for the winter.

In early or mid-April, depending on the spring, remove all the mulch and carefully pull your rose upright and replant the disturbed roots. Water well, then protect the canes from drying out in the spring winds by wrapping with wet burlap or anti-transpirant sprays to conserve moisture as the plant reestablishes itself.