Lenten roses (Helleborus orientalis) bloom in late winter and early spring, adding a burst of cheerful color to the otherwise dreary winter landscape. The plants have evergreen foliage and showy, rose-like blooms that have a waxy texture, which helps protect the plants from frost damage. This low-maintenance herbaceous perennial typically grows 1 to 1 1/2 feet tall and is hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9.
Good plant care starts at the time of planting. Plant Lenten rose plants in a spot with some winter sun, but partial to full shade during the spring and summer. Choose a spot with all-day shade during the summer if you live in USDA zones 8 and 9; if you're in USDA zones 4 through 7, choose a spot that has partial shade during summer afternoons. Additionally, Lenten roses prefer growing in well-drained, rich soil with plenty of organic matter. Mix 2 to 4 inches of compost into the soil before planting to enrich the soil and improve soil structure and water retention.
Because all parts of the Lenten rose are poisonous, be sure to select a planting area away from the reach of young children and pets. Ingesting the plant can cause symptoms such as burning of the throat and mouth, vomiting and diarrhea. Touching the plant may cause minor skin irritation.
Watering and Fertilizing
Follow a regular watering schedule after planting and during the first growing and blooming season. Although you can allow the soil to dry out slightly, you should water the plant thoroughly once the soil 3 inches below the surface feels dry. Check the soil every two days or so and water the plant deeply at the roots, adding at least 1 inch of supplemental moisture every week. If you check the soil and it feels moist, wait and check the soil in another day or two. Once the plant is established, it rarely needs watering unless your area is in a drought.
Lenten rose isn't a heavy feeder. Fertilize the plant annually in late winter or early spring, or when new growth appears, by applying a 2-inch layer of compost or rotted manure around the base of the plant, keeping the compost away from the stems. Alternatively, sprinkle approximately 1/2 cup of a balanced granular fertilizer such as a 10-10-10 formula for each 1 to 2 gallon plant, or follow the manufacturer instructions. Water the plant thoroughly after applying the fertilizer.
Watching for Pests and Disease
Although the Lenten rose is nearly pest free and resistant to most diseases, keep an eye out for several potential problems, including holes in the leaves and flowers, which may indicate slug or snail problems. Dust the foliage, flowers and soil with insect-grade diatomaceous earth by adding the fine powder to a shaker or a puffer, a sprayer designed for powdered products. Give the entire plant a thin coating. Avoid breathing the dust or wear a disposable face mask to avoid irritating your respiratory system.
Other potential problems include aphids, small light green insects that may appear in clusters on the foliage and flowers. They suck the sap from the plant, leaving a sticky substance behind that can leave the plant vulnerable to fungal infection. Aphids can typically be hand picked or sprayed off with a jet of water.
Possible diseases include black death, which causes black streaking on the foliage and distorted or stunted plant growth; destroy infected plants immediately. Leaf spot, which can be identified by the brown patches it leaves on the plant's stems and leaves, is a more manageable problem that can be managed by spraying the entire plant with a pre-mixed, broad-spectrum fungicide.
Pruning Lenten Roses
Prune Lenten roses with clean, disinfected, sharp pruning tools. To disinfect tools, soak them in a solution of 1 part bleach and 3 parts water for five minutes, or spray them with full-strength household disinfectant. Wear gloves to avoid coming into contact with the plant, which can cause skin irritation.
Time your pruning for late winter or early spring as the blooms begin emerging. Remove any old or disfigured leaves, along with any crossing limbs to enhance plant health and allow the flowers to take center stage. The increased exposure also allows insects to pollinate flowers more efficiently. To stimulate vigorous growth, prune plant stems back to right above the blooms.
After the plant has finished blooming in spring, remove spent flowers by pinching or clipping them off of the plant. If left intact, the flowers not only look messy, they also drop seeds that spawn seedlings which take nutrients away from the parent plant.