Winterberry, also called Ilex verticillata, is a slow-growing deciduous holly bush that can grow 6 to 15 feet tall and just as wide. In winter as the foliage falls, the female plant produces hundreds of berries. In order to do this, however, it needs a male plant nearby for pollination. This plant is hardy down to USDA zone 4, where the temperature does not drop below -20 degrees Fahrenheit. Knowledge of the most effective means of propagating the plant and how to nurture it will help you produce a healthy winterberry bush.
Take a winterberry cutting in June or July from a young, healthy shoot. Clip diagonally 4 to 6 inches from the tip of the branch. Fill a small pot with half peat and half perlite and push the cutting 1/3 its length into the potting medium. Water the cutting deeply and place a plastic bag over it to increase humidity.
Maintain the cutting, keeping the potting medium moist but not soaking wet. As it begins to grow and outgrow its pot, transplant it to a larger pot. Do so by placing a layer of potting medium at the bottom of the new pot. Gently take the young winterberry out of its small pot and place it in the larger one. Place more potting medium around the plant until it is snug in the pot.
Prepare a site for the winterberry in early spring, after the danger of frost passes. Choose a site with full sun or partial shade and moist, acidic soil. Once established, this plant will withstand wet soils that occasionally flood as well as dry soils. Dig into the soil about 6 inches with a spade or trowel, breaking up clumps, removing rocks and mixing in organic compost.
Dig a hole twice the width of the root ball and at a depth the same height as the root ball. Place the grown winterberry cutting into the hole. Backfill the soil around the root ball and tamp the soil down around the base of the plant. This will solidify it in the soil.
Water the plant deeply. Keep it moist, but not soaked, until the plant takes root and starts to grow on its own. After that point, give the winterberry one inch of water each week until the leaves drop in fall.