In order to ensure the health and longevity of your garden, spending some time in preparing plants for winter is a good idea, especially if you live in colder zones such as 5 or below.
Winter injury can occur if the plant is unable to withstand cold temperatures, if cold temperatures remain for an extended period of time and if plants are exposed to wind and winter. Usually, injury occurs below the bark or in the buds with bark splitting often occurring close to the ground.
First and foremost it is important to plant in the right locations. For instance, flowering dogwoods and rhododendrons seem to like cool morning sun and cool rather than wet soils. Therefore, it is important when planting to review placement and lessen exposure. Pruning too late in the fall can sometimes stimulate growth and cause winter injury.
Make sure that the plant roots have been well watered prior to cold weather. If you believe that the plant should be covered, ensure that they are still able to get air (or breathe) and never use plastic covering. You can build a wire cage around them (using poles in the ground) and fasten burlap (or other “cloth” material) to the sides. If you are handy, another suggestion is to build small wooden roofs in the shape of an A-frame over the plants, which can be easily removed and stored in spring.
The best way to protect the plant roots is by mulching. Mulching materials can include bark, straw, sawdust, peat moss, leaves, and even grass clippings and should be placed approximately 2 inches deep. If mulching is done close to the house and the soil is dry, it is important to check from time to time to ensure that the plants are receiving enough moisture, and if not, they may require water.
When mulching roses, mound the mulch over the base of the rose canes to a depth of 8 to 12 inches and frame with rabbit or chicken wire. You can fill the wire enclosure with straw for added protection, if necessary. Make sure that you have pruned back the stems and picked off the old leaves, leaving no debris on the ground, since sometimes this will attract insects or cause disease. It is important to use winter fertilizer, especially for roses, such as Greenleaf 6-9-18 or apply a low nitrogen summer fertilizer. As well, in order to protect your roses from insect and disease problems, you can spray a combination of dormant oil and lime sulphur (organic mixture) in late November with follow-up treatments in December and January. This treatment ensures that your roses will remain healthy.
After a cold spell, with extremely dry temperatures, it is essential to ensure that the plants are provided with moisture and often a good watering at this time will protect the plant from damage.
Even if it looks as though a plant has not survived the cold of winter, cut it back in spring and wait and see what happens before disposing of it. Often, a little TLC can motivate the plant to new growth, so be patient and just wait and see.