QWhat is the best method for protecting roses for the winter? Should they be tipped over and covered, or can I just pile soil around the base, or cover the whole plant with straw?
ANumerous hardy shrub roses require no winter protection, but if you want to grow less-hardy types such as tea roses and grandifloras in this climate, you will need to provide fairly extensive winter protection. There are several acceptable ways to protect these tender shrubs.
The most thorough (and most labor-intensive) way to protect nonhardy roses is the Minnesota tip method. The entire plant is partially dug up in about mid-October. Using a spading fork, the soil is gently loosened around the roots, then the plant is tipped over into a trench that has been dug from the base of the plant out. The entire plant is then covered with soil. Once the ground starts freezing (around mid-November), the soil mound is covered with about a foot of dry straw or leaves. (You may need to cover the mulch with some chicken wire fencing to keep it from blowing away.) In the spring, the mulch and soil layers can be removed gradually. The rose plants can be dug up, carefully, about the middle of April. Resettle the plants and water well.
A less difficult method of rose protection is simply piling soil over the crown of the plant in the fall. While this method is effective for many roses in many years, it is not as thorough as the tip method and you may end up losing some rose plants in a severe winter with little insulating snow cover.
If you use this method, make sure you bring the covering soil from another spot in the garden (perhaps the vegetable garden) instead of scraping it up from around the rose plant, because that would expose the outer roots to cold. Use loose, crumbly soil and pour it over the crown and main stem of the plant to a depth of 8 to 12 inches. (You may be surprised to find out how much soil it takes to cover a plant to this depth!) You also may add a layer of dry mulch over the soil. As the weather warms in the spring, gradually remove the mulch and soil, being careful not to damage the plant.
Piling several feet of loose mulch over the entire plant might be sufficient cover in a mild winter, but in a normal Minnesota winter, it will not be enough to protect the tender stem tissue of tea roses.
QDeer have done a lot of damage to my arborvitaes and crab apples the past several winters. Are there any sure-fire methods to keep them away from my landscape plants?
AThere are many suggested methods for keeping deer from browsing on valuable landscape plants, but few would qualify as sure-fire. Deer browsing patterns vary greatly, and a very hungry deer may ignore deterrents that have worked previously.
The only reliable means to exclude deer is with physical barriers. This means fencing, either around your entire yard or around individual plants. For enclosing large areas, the fence must be either quite tall (8 feet or more) or electrified to keep deer out. Fences around individual plants need not be as tall or electrified because deer will not jump into a small enclosure. Make the fence around individual plants is large enough to enclose the branches out to the tips. This kind of fencing is never attractive, but if you have a particularly valuable plant, you may need to fence it.
Nurseries and garden centers sell deer repellent sprays, which often must be applied repeatedly through the winter and may or may not be effective. Most studies I've seen seem to show limited or spotty effectiveness. Other suggested repellents include hanging used bars of soap, bags of human hair or tin cans in the tree you are trying to protect. You can even buy cougar urine (I'm not making this up!) to apply to an area to discourage deer.
Other possibilities are motion detector lights and alarms, though deer seem to get accustomed to these tricks after a few nights -- and your neighbors may not be pleased by the racket. You might try bribing the deer with a pile of corn off in a corner of the yard, but that might encourage more deer.
-- Nancy Rose is a research horticulturist at the Minnesota Landscape Arboretum. She spends her spare time gardening, inside or outside, depending on the weather. To ask her a gardening question, call 612-673-9073 and leave a message. She will answer questions in this column only.