By Nancy Knauss ©2012
Penn State Extension
It is hard to imagine flowers blooming outdoors in February, but the Christmas rose (Helleborus niger) delights gardeners with its charming pure white blooms that emerge from the plant even when frost and snow lie on the ground.
Most gardeners are familiar with Lenten rose (Helleborus orientalis) and eagerly search out the newest introductions boasting double flowers, speckled petals and amazing colors. But don't neglect the austere beauty of the Christmas rose. Unlike most hellebores with nodding blooms, the snowy white flowers of the Christmas rose face outward, proudly posing for all to enjoy.
Hellebores' 2-inch blooms are unusual in that sepals -- not petals -- put on the show. The five sepals surround a large cluster of yellow stamens and hide the numerous inconspicuous petals. The flowers can persist for two months or longer, depending on temperature. As the sepals mature, they take on rosy pink or green hues.
Seed pods form soon after pollination. By the time the seed matures, the sepals have faded to green and the seed pods are swollen. Remove the seed pods to encourage robust plants, or leave them alone and numerous seedlings will develop around the base of the plants.
Helleborus niger is hardy in zones 3 to 8 and typically grows 12 to 18 inches tall. Hellebores are divided into two groups: those with stemless foliage that arises from the rootstalk of the plant, and those that produce an above-ground stalk from which leaves develop. The Christmas rose falls into the stemless category, referred to as acaulescent. The smooth, dark blue-green leaves are leathery, palmately divided, and have serrations on the leaf margins. Often the evergreen foliage is borne on red stems.
Plants thrive in partial shade that is rich in organic matter. They are perfectly suited to a woodland garden and will develop into a lush ground cover over time. Unlike the Lenten rose, the Christmas rose is planted with the crown just below the surface of the soil. It typically grows in a limestone soil, but plants readily adapt to a neutral or slightly acidic soil. However, amending the area with an alkaline organic material such as mushroom manure is helpful. Plants will also benefit from an annual sprinkling of ground limestone. Helleborus niger is slow to mature but it will form large showy clumps that will remain vigorous for years. They are durable plants and will thrive with minimal maintenance.
The plants can be divided in the spring, but Helleborus niger often suffers a setback after division and may not bloom for several years afterward. It is preferable to propagate the plant by transplanting the seedlings that develop around the base of the plants.
The Christmas rose is relatively insect- and disease-free, although it may be plagued by fungal leaf spots that cause brown, desiccated areas.. Prevention is important; clean up old stems, leaves and debris that may harbor disease and overwintering insects. Copper-based fungicides are helpful in preventing leaf spot if the problem is treated early. Plants are also subject to winter injury from cold winter winds that may cause desiccation of the foliage. Because of their toxicity, hellebores are generally not browsed by deer.
A small vase of flowers brought indoors is a perfect pick-me-up for the winter blahs. Although somewhat finicky to conditions when fresh, best results are obtained if you cut the flowers just as they are beginning to form seed pods. At this stage they condition well and will last for several days indoors.
If you decide to cut the flowers when they are young, they will benefit from the boiling water treatment. Immerse the ends of the stems in boiling water for about one minute. This technique forces air from the stems and allows for better uptake of water. After the boiling water plunge, re-cut the stems and immerse them in water overnight.
Whether enjoyed indoors or outside, the Christmas rose is a wonderful sign that spring is not too far away!