Some gardeners, even in the colder zones, wait to winterize roses until late fall when all the roses are completely dormant. But the weather is unpredictable by mid-fall, and a sudden cold snap could cause serious damage.
There isn’t just one way to winterize all your roses. How your rose fares in winter depends on a number of factors – the weather, the plant’s location in the garden and, of course, the type of rose. Some varieties are more naturally hardy than others. Temperate zones (USDA Zone 6 and warmer) are easier on roses, and roses planted close to the house are more sheltered than those out in the open. Check with your nursery or local rose society if you aren’t sure whether your varieties are hardy. If there’s a graft on your rose bush, it’s a newer variety and probably not hardy.
Tender varieties of roses can be seriously damaged in places where the temperatures dip below 20 degrees. But there’s an easy way to protect them with a technique called the “Minnesota tip.” It was developed in the 1950s by a Minnesota gardener and involves tipping a rose bush into a trench.
Prune the bush to three feet tall, cutting above outward-facing buds. Remove smaller limbs, leaving three to five of the thickest, most vigorous canes.
If there are any leaves, pull them off. Aside from harboring disease, leaves can increase drying.
Tie the canes together using synthetic twine that will not decay over winter. Tie by starting at the bottom with a slip knot and lacing up the plant. Leave a long piece of twine attached.
Spray the canes with dormant oil spray, which protects them from diseases in the soil. Mix 5 tablespoons of the oil with 1 gallon of water. Or, if you’ve already made a baking-soda solution (1/3 cup baking soda to 1 gallon water) to spray as a fungicide, you can simply add the dormant oil to that to save time. Coat the canes well and let dry.
Dig a trench on one side of the plant and loosen the soil around the roots using a garden fork to minimize root damage.
Add fallen evergreen needles to the trench and mix with the topsoil. The high acidity of evergreens is great for rose beds.
Use a garden fork to pry under the roots and carefully tip the plant over into the trench.
Cover the plant completely with the soil that was removed, being careful to leave the long piece of extra twine exposed above the dirt so it will be easier to find later.
Water the bed to help settle the soil and keep the canes and roots in good shape for the winter.
Cover with a carpenter’s blanket and bags of leaves to keep it in place. Bags of leaves are easier to deal with in the spring than loose leaves, but for small areas loose leaves may be fine and will decompose.
This process can be used for all varieties of nonhardy roses – from standard to miniature. By early April when days are warmer and longer, remove the leaves, and then a few weeks after that, uncover the bush, untie it and get it ready for a summer of beautiful flowers.