Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
10/23/00
Contacts:
Richard Jauron, Horticulture Extension, (515) 294-1871,
rjauron@iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Yard and Garden Column for the Week Beginning Oct. 27
Winter Protection for Roses
By Richard Jauron
Extension horticulturist
Iowa State University Extension
Iowa's winter weather can be brutal. Most modern roses grown in the state require winter protection. Exposure to low temperatures and rapid temperature changes injure and often kill unprotected bush-type roses, climbing roses and tree roses.
Bush-Type Roses
Bush-type roses include hybrid teas, floribundas and grandifloras. An excellent way to protect bush-type roses is by hilling or mounding soil around the base of each plant.
Begin by removing fallen leaves and other debris from around each plant. Removal of diseased plant debris reduces disease problems next season. Then loosely tie the canes together with twine to prevent the canes from being whipped by strong winds. Next, cover the bottom 10 to 12 inches of the rose canes with soil. Place additional material, such as straw or leaves, over the mound of soil. The straw or leaves can be held in place with chicken wire fencing or by placing a small amount of soil over the materials.
Many home gardeners protect their bush-type roses with plastic foam rose cones. Unfortunately, rose cones by themselves don't provide adequate winter protection. Additional protective materials are usually necessary. If using plastic foam rose cones, prune the canes back to allow the cone to fit over the plant. Remove any plant debris, then mound 6 to 8 inches of soil around the base of the canes. Set the cone over the plant. Finally, mound a small amount of soil around the outside base of the cone to keep it in place. Secure the cone by placing a brick or other heavy object on its top.
Climbing Roses
Most modern climbing roses bloom on the previous season's growth. If much of the plant is destroyed during winter, these types of roses will produce few if any flowers.
To protect climbing roses, remove the canes from the trellis or support and carefully bend them to the ground. Hold the canes to the ground with pegs or stakes, then completely bury the canes with several inches of soil.
Tree Roses
Tree or standard roses are produced by bud-grafting the desired rose variety onto a tall stem. Since the cold-sensitive bud union may be 2 or 3 feet above the ground, tree roses are extremely vulnerable to winter injury or death. (Tree roses are best suited to areas with mild winter climates.)
The first step in protecting a tree rose is to decide which direction to lay the plant. Then loosen the soil in the opposite direction with a spade. Put the blade into the soil about 1 to 1 1/2 feet from the base of the stem. Then gently rock the spade back and forth to loosen the soil and free the roots. Loosen the soil in a semicircle around the plant. On the other side of the tree rose, dig a shallow trench and then carefully bend the trunk (stem) down to the ground. Peg the stem down with stakes. Finally, cover completely the tree rose with several inches of soil.
Tree roses growing in pots or other containers also need winter protection. Dig a trench in the garden, lay the potted tree rose in the trench, then cover with several inches of soil.
Prepare roses for winter after plants have been hardened by exposure to several hard freezes. Normally, this is late October to early November in northern Iowa, mid-November in central areas and mid- to late November in southern counties.
Remove the protective materials before bud break in spring, normally late March in southern Iowa and mid-April in northern Iowa.
With the proper protection, modern roses can survive the harshest of winters and bloom beautifully next summer.
ml: isugarden
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