Winterizing Raspberry plants Asked October 17, 2016, 1:35 AM EDT We moved to Colorado three years ago and in trying to clear the back yard for a garden, I tried to remove some raspberry plants … This extended watering prevents over-drying during the winter and also helps harden the plants and prepare them for the cold. the main mass of roots on a plant… There are dozens of raspberry cultivars, but not all are suited for container … If you live north of zone 6, a few simple steps will ensure that your plants survive to see the next spring. Tip Raspberry bushes that … The best container for growing raspberries has a diameter and a depth of at least 24 inches (60 cm) and has drainage holes. When pruning the canes, cut them down to the soil level. Continue watering the raspberries long after the plants have stopped producing fruit, and don't hold off on watering until the first frost. Raspberry bushes must be protected from freezes during the growing season, though in most warm-winter areas, this type of freeze is rare. Use frost tolerant containers if the plants will remain outdoors in very cold weather. Depending on the variety, strawberries and raspberries are cold hardy to U.S. Department of Agriculture plant hardiness zones 3 or 4, but they do need some protection during harsh winters. Winterize Raspberry Plants. The right pot size and soil type The size of the container depends on the size of the root ball (i.e. “Potted berries can be watered once a month in the winter if no winter rain is present, as this keeps the roots healthy,” says Davis. Choose the Right Cultivar.