Growing Concerns 557: Overwinter tree roses, relocate?

Late Winter!

Tree rose is unlikely to survive winter so try a different vertical feature


Dear Janet,

Some tree roses are said to be "hardy" to zone 5 and 6. Does this mean they could get through the winter without being trenched? I know that the graft is at the top. Is it possible to insulate the graft and hold it there with burlap? Any other ways to overwinter tree roses?


Dear R.,

I'm glad you posted that question on the discussion forum so it could be fielded by Nancy Lindley, owner of Great Lakes Roses and author of the excellent and much needed new book "Roses for Michigan" (Lone Pine Press).

Says Lindley, "I don't know of any grafted tree roses (technically called "standards") that are hardy in Zone 5. The variety grafted to the top may be hardy, but the graft isn't."

"A very few nurseries offer non-grafted tree roses and those can be hardy. Basically, they take a rose bush that has pushed out a big, tall cane. They stake that cane and prune away all the other canes. These roses don't look as graceful as a well-done grafted tree rose, because top-notch tree roses have at least four bud eyes grafted to the top of the shank. Also, you really have to keep on top of a non-grafted tree rose and prune out any new growth from the base, before it overtakes the rest of the plant."

"You grow tree roses for vertical interest in your garden. Why not select a small, hardy climber and grow it up a narrow obelisk? It can stay outdoors all winter long and will give you nice vertical interest."

Short reports

Never overlook the simplest answer, to relocate the plant!

Recently in this column the hot topic has been how to guard plants from conditions that don't suit them, such as how to keep rhododendrons and other broadleaf evergreens from drying out over winter. You're not alone if you think it's too much trouble to spray protective coatings on these shrubs in late fall, then use a last-minute vacation day during a late winter thaw to renew the treatment. I feel the same way. There is a simpler way to prevent winter damage to evergreens, and that's to move the plants to the site they should have been in all along. That's a place that's out of the winter wind and midday sun.

Plant pest experts at universities agree that an overwhelming majority of insect and diseases become problems only when the gardener gives them an opening. We open the door by choosing disease-prone species, putting plants in places where they cannot receive the combination of light and water that will make them resistant to trouble, or by improper watering, fertilizing or pruning.


Green thumbs up

to brave early flowers that warm the heart by blooming at the first possible minute, sometimes opening up within a garland of snow. Snow crocus (Crocus minimus), snowdrops (Galanthus nivalis), winter aconite (Eranthis hyemalis) and spring witchhazel (Hamamelis x mollis) will open any day. Lenten rose (Helleborus x orientalis) and Iris reticulata will follow close behind. Skunk cabbage (Symplocarpus foetidus), a handsome and intriguing plant despite its unfortunate name, may beat them all, having literally melted its way up through the ice at ponds edge. Perhaps even more amazing is the fact that the day these flowers open, bees will find them!


Green thumbs down

to the trash that's melting out of the snow banks. Vile sneaks! We know we didn't scoop that debris into the snow as we piled it, so how did it arrive there? Worst are those items that refuse to be removed, such as shredded plastic bags with exposed portions fluttering in the breeze while their bases are still frozen in place.


Originally published 3/6/04