Nearly all types of roses require some amount of protection during the winter months. However, the extent of protection required by your roses depends on the severity of cold in your area during winter and the hardiness of your roses. When we talk of hardiness, we refer to a plant’s ability to remain in a dormant stage during the harsh winter months and not die due to the cold weather conditions. When a plant enters a dormant phase, it is basically in suspended animation, as there is no growth either above or under the ground. However, tender plants do not possess the ability to endure such cold and often die during the winter.
The hardiness of different types of roses differs greatly. While no area-wise hardiness report for different varieties of roses has ever been compiled, one can make some generalizations. In general, old garden roses, shrubs and miniature roses have the propensity to be tough, while others like China roses, tea roses, modern bush roses and noisette roses are generally tender and unable to endure harsh conditions.
Natural Winter Protection
It may appear to be incredible, but the deep blanket of snow provided by nature is possibly the best protection against the extreme cold during winter. Interestingly enough, snow ensures that the temperatures below do not fall much below the freezing point. At the same time, it does not allow the temperature to rise very high or quickly, which may deceive the plants to start premature growth. In addition, snow also wedges the wind effectively and also takes away the excessive moisture from the soil as well as the rose canes. On the other hand, snow can also prove to be disparaging, as its weight may break or even deform the branches, especially of the larger rose varieties. Therefore, it is advisable that you dispose of the sagging branches following a snowfall. In case you reside in an area where there is heavy snowfall often, you may even fasten the larger plants collectively using strings with a view to providing them with support against the snow’s weight.
Additional Winter Protection
In the majority of areas, it does not snow too often or too deep that necessitates continuous insulation. Therefore, you have to depend on other winter protection means too. Such methods may include enveloping the plants with any insulating material and/ or burying the plants partly or fully. If you are growing your roses in containers, you should move the plants indoors before the first expected date of frost in your area. The appropriate time to provide the outdoor plants with winter protection is in fall. Precisely speaking, this should be dome immediately following the first usual hard breeze that actually shocks the plants to go into dormancy. If you are applying any covering to protect the plants from cold, they should not be taken away before spring. In addition, you should remove such coverings gradually. Preferably, the coverings should be removed when the warming speeds up with a view to lessening the possible losses due to any unexpected freeze late in the season. While you are doing away with a winter covering, you need to be cautious not to damage or break any cane that may have grown since you saw the entire plant last.
One of the conventional means to protect roses from the winter cold is to place soil mounds on the pedestal of the canes. Preferably, the mounds should be roughly 12 inches in height. This will help to protect the bud unions, which are extremely vulnerable to frost. At the same time, it is important for you to fetch the soil for mounding from a different area of your garden. This is mainly because digging up soil from close vicinity of the roses may lay the plant’s feeder roots bare to cold air, thereby damaging or even killing the plants.
While the soil mounding method discussed above is very effectual, it necessitates plenty of work, as it involves bringing in the soil to your garden during the fall and again removing it when it is spring. There is another equally effective method that does not require so much hard work. Instead of soil mounding, you may apply a cover of lightweight organic material that is non-absorbent up to 12 inches at the base of the canes. This method is also known as winter mulching. Some organic materials that are excellent for this purpose include straw, shredded oak leaves or the green parts of the discarded or unsold Christmas trees that are easily available after the holiday season. When it is spring and the soil starts warming up, there are two options before you – either remove the winter mulch or use the organic material properly to enhance the quality of the soil.
There are other ways to provide winter protection to your roses. For instance, you can use particular rose cones that can be purchased from large garden centers and also from hardware stores. These rose cones are made from polystyrene and have thick and expandable walls. They come in rounded shapes or as multi-sided containers tapering toward the top. They also come with flanges at the base and these can be used to pin them down the cones to the soils or even weighted. Some rose cones come with solid tops while there are others that come with covers, which can be taken away when the days are warmer with a view to preventing the plants from coming out of their dormant state prematurely. Some gardeners make vents by making holes at the top of the cones to augment air circulation, which may help to lessen mold growth.
Here is some additional information for gardeners wanting to use rose cones to protect their plants during the winter. These rose cones are available in two different sizes – one is an economical variety measuring about 12 inches in height while the other is a little expensive and measure about 18 inches in height. The second variety of rose cones is meant for gardeners who dislike pruning their roses too much to fit into a smaller rose cone. Nevertheless, even while using the lager rose cones, it may be necessary to prune the larger roses heavily. Roses will fit inside a cone better if their canes are fastened together using a string before placing them under the cones. Rose cones are reusable. You can stack them when not in use during summer and use them again during the next winter. Generally, they last for several years.
Apart from using the techniques discussed above, there are some natural ways that will help to keep your roses healthy and resist the harsh cold during the winter months. For instance, the roses will over winter better if they are looked after well during the summer. It is important to keep the roses in good health during summer for them to remain healthy throughout the winter. It is important to note that roses that are watered timely and appropriately, fed properly and are free from diseases and assaults from insect are the ones that survive winter better. On the other hand, roses that are maintained poorly during the summer months generally do not have a satisfactory survival rate during the winter.
What Causes the Damage to Roses in Winter?
Many people often wonder what actually damage their roses during winter. Simply speaking, the answer to this is very easy, but surprising. Water is responsible for most of the damages to roses during the cold months. During their entire growing season, roses enclose water in their cells. When the temperature drops all of a sudden, the water present in these cells freezes, thereby causing the cells to enlarge and eventually rupture. This not only damages the roses but also kills them. On the other hand, when a rose gradually enters its dormant state, the cell walls have sufficient time to first thicken and allows the water to change into a form that combats freezing. In fact, water in the cells turns into a form of liquid that is somewhat akin to an anti-freeze. This prevents the roses from being damaged. Cold-hardiness of roses can be described as an extent to which the roses can convert the water in their cells into this anti-freeze liquid.
Is Timing Important?
Generally, roses have the aptitude to endure extremely low temperatures and yet not be damaged when they are in a dormant stage. Therefore, it is advisable that you keep the roses in a dormant state for a longer period when the temperatures are extremely low. You can achieve this by providing winter protection quite early – much before the ground freezes. This will not only help to keep the soil warm but also delay the dormancy state of the plants.
Preparing Your Roses for Winter Months
Below are a few tips on how to prepare your roses to enable them to over winter successfully.
Never fertilize your roses after August, because fertilizing the plants will encourage the growth of new shoots and they will be unable to withstand the harsh cold during the winter months. At the beginning of September, you need to check the rose bush base with a view to seeing if there is any new growth. In case you find any new growth, remove them immediately to avoid any freeze injury to the plants at the beginning of the season.
Start reducing all manual watering to the plants right from early September. When the roses take in less water around this time of the year, it facilitates them in their hardening process and prepares them better for entering a dormant phase.
At the same time, ensure that the base of the rose bushes is clean. Remove all dead leaves as well as debris in the region of the rose bushes, as this will help you to get rid of insects, which may afflict your roses. In addition, keeping the base of the rose bushes clean also helps to prevent the roses from developing diseases that may remain there and survive the winter.
If any rose bush has been enduring insect problem during the summer months, ensure that you spray them with any effective dormant oil. Apply this oil to the rose canes as well as the surface of the soil. However, this should only be done when your roses have already entered the dormant state.
Also, ensure that your roses do not become dehydrated, which may be caused due to low humidity together with intense sunshine and strong winds during the winter months. When the plant is already in their dormant state, spray them with Wilt-Pruf, a product that prevents plants from wilting, as this will help your roses to battle dehydration better. In case the winter months in your region are arid, you should water the roses once in three weeks to prevent them from becoming dehydrated.
Remember that you do not require pruning your roses during the fall. However, some light pruning can be undertaken to cut back any cane that has grown excessively long and faces the risk of being broken off due to heavy snowfall or strong winds. The earliest, as well as the best time to prune your roses, is April end.
Specific Needs of Rose Species
Apart from all things discussed above, you should know that particular varieties of roses have some individual requirements. Providing them with their specific needs will go a long way in helping them to survive the cold winter months better. A few tips regarding the specific winter survival requirements of some roses are given below.
- Miniature roses
- Since these roses are extremely enduring, you need to provide them with very little winter protection. As the miniature roses are relatively small, it is much easy to protect them from the harsh winter. You may provide mulch mounds in the region of the miniature rose stems up to a depth of anything between 4 inches and 6 inches – adding the mulch to a height of roughly 3 inches around the plants above the soil surface. You can use almost any organic material for mulching the plants. They may include tree bark, evergreen branches, straw, leaves and even soil. In case you prefer using soil for mulching, make sure that you obtain this soil from a different part of your garden or elsewhere. If the soil from the area close to the plant is used, there is a danger of exposing the feeder roots of the plants to cold and winds. At the same time, it may also harm the surface roots. When it is spring, remove the mulch gradually with a view to providing ample time to the plants to get used to the normal sunlight and wind again.
- Compared to hybrid teas, these rose species are more enduring. Nevertheless, providing them with adequate winter protection will help them to survive the harsh cold better. You may treat the floribundas in the same manner as you would look after the miniature roses during the winter months. Mulch the plants to help them to remain dormant throughout the winter.
- Shrub and old garden roses
- Since they have a long life span, these roses can endure winter better than most rose species and varieties and usually do not require much winter protection. Nevertheless, providing these plants with organic mulch mounds will increase their winter protection.
- Hybrid teas
- While purchasing hybrid tea roses, only opt for those that are suitable as well as resilient to conditions prevailing in your region. Winter protection of these roses includes covering the base of these plants with 12 inches or more of mulch. Ensure that you get the soil or mulch from another part of your garden or anywhere else so that you don’t disturb the base of the plants, thereby damaging their roots that are close to the surface. It is necessary to hold the mulch around the plants and not allow it to be blown away be strong winds. To achieve this, you can use plastic rose collars or wire mesh cylinders, measuring at least 12 inches across. These rose collars and wire mesh cylinders can be obtained from any garden center in your neighborhood. Remove the mulch little by little in the middle of April. Alternatively, you can also use a foam cone that can be used to cover the entire rose plant to protect it from the winter cold. However, one will require pruning the roses in order to fit the foam cone over it. The pruning should essentially be done much before winter set in because pruning is not recommended during the winter months. In fact, the foam cone is not considered to be an ideal winter protection for hybrid teas because it makes the plant gets heated in small warm spells, which disturbs the dormant state of the roses and stimulate new, unwanted shoot growth.
- These roses grow very tall and their height usually creates a problem in providing them with appropriate winter protection. When the climbers are already in their dormant state, remove their canes from the supports, tie them together and place them horizontally on the ground. Subsequently, wrap the climbers with burlap and fasten them in a manner that they remain fixed in a place. Doing this will protect them from any damage by strong winds.
- Tree roses
- These roses are probably among the most difficult to protect during the winter. You can protect these roses by two methods, provided you want the plants to remain outdoors during the cold winter months. First you need to wrap the plants in burlap, right from the ground level to the highest point. Wrap the roses in a manner that the graft is covered. Next, slacken off the soil in the region of the roots, dig a trench, bend the plant over and wrap up the entire plant using mulch. Alternatively, you may also excavate the entire rose tree; place it in a cool location such as a garage or in a basement till spring. At spring time, replant the rose tree in its original spot outdoors.