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YARD AND GARDEN

Give roses special care for lasting beauty

Roses are one of the wonders of the plant world — how many times does a thorn bush produce such a wonderful flower? On the other hand, how many times does a thorn bush need so much protection during the winter?

Roses are those rare plants that look great, but require almost more care than they are worth.

Dave Robson

It's tough and sometimes complicated to get a rose to overwinter. Plants are notoriously susceptible to cold temperatures as well as freezing, thawing and heaving of the soil. Roots are readily snapped and that doesn't bode well for the plants.

A key factor to successfully overwintering roses is in applying a protection that will help maintain a constant temperature around the plants. In other words, once it gets cold, you want the plant to stay cold until next spring. The goal is to protect the plants from sudden temperature fluctuations. Never look at protection and mulching to keep roses warm.

Roses must be allowed to harden off and reach dormancy before any winter protection is applied. Anything that keeps the plant growing delays dormancy and reduces winter hardiness.

Covering plants early, often before dormancy has been completed, is thought to be a major factor of winter rose mortality. In northern Illinois, mid to late November is generally the time to apply winter protection for roses. In central Illinois, mid to late November is ideal, and in southern Illinois, the first week or so of December should be ideal.

There is no one correct way to ensure survival. Even rose growers disagree, with many having elaborate styrofoam houses prepared while others simply cover the plants and hope for the best.

Before covering, prune plants lightly to prevent winter winds from whipping the cones and loosening the root system. Plants shouldn't be pruned back shorter than 3 feet if possible unless they need to fit beneath a shelter of some form. Tie the canes with something flexible such as nylon hose to limit wind movement.

Avoid pruning plants back severely. Additional pruning should be done in early spring when winter protection is removed. Remove fallen leaves and pruning debris. Any foliage left on the plants should be removed. If disease has been a problem, a fungicidal spray should be applied.

As cold temperatures occur in the fall, place a mound of soil around the crown or base of each plant. To avoid injury to plant roots, soil should be brought to the garden from another part of the yard. Soil mounds should be 8 to 12 inches high.

As the soil begins to freeze, but before temperatures drop below zero, top the ground with a foot of straw, wood chips, shredded bark or loosely packed leaves. Lay chicken wire over the mulch to keep it from blowing away.

The cone approach to rose protection is simpler, but doesn't guarantee success; in fact, survival rate can be lower. For more insulation, bury the plants under a soil mound and in mulch before covering. Canes should be cut back to fit beneath the cones.

If you use cones, delay putting them on until the first sign of ground freezing. This usually occurs in early December, but could occur later.

Cones are easily blown off so weight them down with rocks or a brick. Punch holes in the sides of the cone to provide ventilation and to prevent heat build-up inside the cone. This is essential. Individuals who use rose cones may need to periodically remove or ventilate cones during late winter warm periods in order to reduce heat build-up within the cone.

Another idea is to encircle plants with a cylindrical column made of fencing material and filled with loose material such as straw. Columns can also be made from discarded boxes, sections of old newspaper stapled together, or tomato cages. When filling the columns, avoid materials that will pack or hold excess moisture such as leaves.

These cylinders can be great winter hiding places for mice and voles that may feed on the rose canes. Chicken wire fencing does reduce the possibility.

Finally, hope for a mild winter.

David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, Cooperative Extension Service, University of Illinois. You can write to Robson in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: (217) 782-6515. E-Mail: robsond@idea.ag.uiuc.edu

16 ILLINOIS COUNTRY LIVING NOVEMBER 1998