Grow hellebores (Helleborus spp. and hybrids) in a shady garden or corner in the yard for rich, green foliage and flowers through the cold, dreary winter months. They are generally hardy in U.S. Department of Agriculture plant hardiness zones 3 to 9, although this varies slightly from species to species. In USDA zones 3 to 5, the stems die in late fall but sprout again in late winter. Hellebores are evergreen in USDA zones 6 to 9.
Hellebore Species and Hybrids
Plant Christmas roses (Helleborus niger) for white flowers that fade to light pink in USDA zones 3 to 8. They grow to a height of 9 to 12 inches and bloom around the end of December in warm climates. In colder climates, they bloom in February or March. Go with Lenten roses (Helleborus orientalis) for flowers a little later in the season. They bloom in March in warm climates and April in cooler climates. The plants grow to a height and width of 1 to 1 1/2 feet. Blooming time for all hellebores will vary somewhat, depending on the severity of winter weather.
Ballard’s Group hybrids (Helleborus x hybridus Ballard’s Group) bloom from February through April, producing black-purple, pink, red, maroon or yellow flowers. They are hardy in USDA zones 4 to 9, where they grow to a height and width of 1 to 1 1/2 feet.
Sunlight and Soil
Grow hellebores in partial to full shade. Dappled shade all day or morning sunlight with afternoon shade is best in warmer USDA zones 8 and 9. Increase organic matter prior to planting with a 2- to 3-inch layer of well-aged cow manure, compost, leaf mold or composted pine bark mulch. Mix the organic matter thoroughly into the top 8 to 10 inches of soil. Hellebores thrive in alkaline soil with a pH of 7.6 to 8.5 but grow just fine in acidic soil with a pH as low as 5.5. The soil must drain quickly.
Plant hellebores in the fall at least six weeks before the ground usually freezes. Plant them at the same depth they were growing with 1 1/2 feet between multiple hellebores or other plants. Water them generously after planting. Spread a 2- to 3-inch depth of organic mulch over the soil around them to help conserve moisture.
Water and Fertilizer
Water hellebores when the soil begins to dry. Sprinkle slow-release fertilizer around them in late winter when they begin to grow new foliage. Use fertilizer with a balanced analysis of 8-8-8 or 10-10-10. Spread 2 1/2 cups of 8-8-8 fertilizer per 100 square feet or 2 cups of 10-10-10 fertilizer. Do not get fertilizer on the leaves. If that happens, brush it off right away.