Developed by German nursery director, Reimer Kordes, in 1958, Iceberg is a floribunda rose cultivar that is created by hybridizing Rosa Robin Hood and Rosa Virgo. Prized for its honey-scented light green foliage and creamy white blossoms, iceberg roses make a charming addition to home gardens and landscapes in U.S. Department of Agriculture plant hardiness zones 4 through 9. Growing iceberg roses is a simple and rewarding task for both novice and veteran gardeners.
Plant iceberg roses in a location that is exposed to at least six hours of direct sunlight daily to encourage healthy growth and development. Note that planting iceberg roses in locations that receive less than six hours of daily sunlight will inhibit blooming. Plant your iceberg roses in well-draining soil to reduce the risk of harmful fungal diseases.
Water iceberg roses regularly throughout the growing season to keep the soil evenly moist, but never saturated. Provide your roses with 1 inch of supplemental irrigation each week in the absence of sufficient rainfall. For best results, water your iceberg roses via a soaker hose to ensure that the moisture soaks deep into the soil.
Fertilize iceberg roses twice each growing season with a balanced, water soluble rose fertilizer to promote healthy foliage and flower growth. Apply the first application of fertilizer in the early spring to give your roses a much-needed boost of nutrients. Wait until the roses have started blooming to apply the second fertilizer application. Consult the application instructions on the fertilizer packaging.
Provide winter protection for iceberg roses in cold climates. Mix equal parts sandy loam and well-rotted compost until well combined. Form the mixture into a 10- to 12-inch mound around the base of your rose bush; do this before the first fall frost, if possible. Remove the mound in the early spring, as soon as you notice the buds on your iceberg roses beginning to swell. Leave 3 to 4 inches of the mound in place to serve as mulch, if desired.
Prune iceberg roses each spring, once the leaf buds have opened. Use a pair of sharpened and sterilized pruning shears or loppers to cut out any diseased, winter-damaged or dead canes. Remove any crossing or weak canes to increase the air circulation to your roses; lack of circulation can increase your plant's risk of developing problems such as powdery mildew. Cut any remaining canes back by one third to encourage invigorated growth.