University of Vermont Extension 
Department of Plant and Soil Science

 Summer News Article

HARDY ROSES
 
By Dr. Leonard Perry, Extension Professor
University of Vermont
 

If you've tried growing roses in our cold northern climate, only to have them die, you may have given up. But don't, as there are many varieties that are hardy and will survive with little care.

The most common problem in choosing roses is trying to grow all the latest hybrids you see advertised in the glossy magazines and catalogs. Most of these are modern hybrids, and are only marginally hardy in the warmest parts of Vermont or warm microclimates on your property. These small areas of warmer temperatures might be in front of a south facing wall or side of a building, or on a south facing slope.

Of the so-called "modern roses" (those developed since what many consider the first hybrid tea rose 'La France' in 1867), the ones most commonly seen in garden centers and through mail order include hybrid teas, floribundas, grandifloras, miniatures, and climbers.

Another five classes of roses are in the "modern" group, of which the shrub and rugosa hybrids are often hardy in Vermont. Even though these latter ones were first developed in the late 1800s, many selections have been developed since then which are available now.

Of these selections, several series are seen in our area. The Explorers were developed in Ottawa at the Experiment Station and are named after famous Canadian explorers. The Parkland series was developed in western Canada at the Morden Experiment Station and carries names such as Morden Centennial.

The Meidiland series is from France, and usually has "Meidiland" in the name, such as Meidiland Pink. Then there are the David Austin English garden roses, beautiful and fragrant and fairly resistant to diseases, but most in this series are not hardy in most of Vermont.

The 15 or so classes of "old garden roses" mainly were developed prior to 1867. These classes and groupings of old and modern roses may differ slightly with each rosarian (or rose fancier) and reference. Of these, the ones that are most hardy for our area include the albas, gallicas, damasks, and centifolias.

We are testing some of these potentially hardy roses at the University of Vermont Horticulture Research Center in S. Burlington--a U.S. Department of Agriculture zone 4b, which gets on the average -20 to -25 degrees F in the winter. Since we can only test some of the hundreds of varieties available, there are likely many more that will grow well in our area.

Our test site is a sandy soil, and plants are watered, but minimally. The snow cover is not reliable, often blowing off, so plants often are subject to colder temperatures than if in colder but snowier parts of the region.  In addition, the plants do not have their cold-sensitive graft union (the swollen part at the base) buried as is normally recommended. So if they survive several winters, we feel confident that they are fairly hardy in areas of similar winter cold.

Of those "old" roses we've tested, the best species roses have been acicularis (rose-colored flowers), zanthina (yellow), and primula (yellow). All five albas we tested are hardy, including alba maxima (white), Felicite Parmentier (pale pink), Koenigen von Daenemark (pink), Maiden's Blush (pink), and Pompon Blanc Parfait (white).

The best gallicas for us include Conditorum (purple-red), Rosa Mundi (pink and red), and Tuscany (dark red). The best damask ones were Madame Hardy (white) and York and Lancaster (white and red).

Of the modern series, only the pink and white Meidiland survived poorly. Six other cultivars died. David Austin roses have performed in a similar manner, with only three of the eight cultivars tested surviving poorly. Parkland roses have not been reliable or have not survived, with the better of the group for us being Cuthbert Grant (wine red) and Prairie Dawn (pink).

The Explorer series has performed the best, with most cultivars tested, and the only one not reliably surviving being Champlain. Of the Explorer series, we saw the best results with Charles Albanel (pink), David Thompson (pink), and Henry Hudson (white).

Many shrub roses died, but ones surviving well included Canary Bird (yellow flowers), Magnifica (pink to red), and the groundcover Seven Sisters (pink). Most of the rugosas survived except Agnes, Parfum de l'Hay, and Schneezwerg.

The rugosas are one of the most rugged groups of shrubs in general, withstanding all kinds of stress including salt spray along roads and by oceans. You may see them along roads and in parking lots for this reason.

You can grow the less hardy series and modern roses, such as the hybrid teas and David Austin varieties. But you often have to grow them as an annual. Often people shudder when I mention this, but I try a couple each year, get blooms all summer, and feel I've gotten my money's worth. Then if they don't survive, I merely try a couple of new varieties next year.

So do give roses a chance in your garden, but look for some of the hardier varieties. Look for fragrance if this is important, as not all shrub types are fragrant. Be aware, too, that many of these are "once blooming," blooming for two to three weeks in June and then not again, unlike the modern hybrids.

Some of the hardy shrub types though are "recurrent" and more or less bloom through the season, such as the David Thompson explorer rose. What you often trade off in continual bloom you get in hardiness, with little or no care or winter protection needed.



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