Helleborus (Christmas or Lenten rose)
Type: Perennial, Shade. Blooms late winter/early spring. Rich, well drained soil.
Exposure: Hellebores prefer dappled or partial shade. Drought-tolerant once established,
Watering: Water during dry spells.
Fertilizer/Soil and pH: Hellebores grow best in evenly moist but well-drained soil enriched with copious amounts of organic matter. The hybrids known as Helleborus x hybridus (previously called Helleborus orientalis) prefer a soil pH close to neutral and even alkaline; add lime if your soil is extremely acid. Plants will benefit from a light application of granular, balanced fertilizer in early spring or side-dress with compost and organic amendments when new growth appears. Avoid planting in very dry or waterlogged soil. Mulch annually with leaf mould, chipped bark or other organic matter. In autumn add lime to acid soil for H. x hybridus if a soil test shows a pH under 7.0.
Pests/Diseases: Watch for slug or snail damage, and control with baits or diatomaceous earth. Remove any dead, diseased or damaged foliage that can harbor hellebore leaf spot, an unsightly fungal disease.
Pruning: The flowers of hellebores are often hidden by the large leaves, so ensure they can be seen clearly by removing a few older leaves from the center of the clump. Exposing the flowers in this way will also help insects to pollinate the flowers and ensure good seed set for new plants that can be propagated from the resulting seed.
Do not prune in winter. Although evergreen, the foliage often looks tattered in early spring. Prune back dead and disfigured foliage before new growth appears. Remove old flower stems when they decline, cutting back to basal foliage, but take care not to remove the stems of Bear’s-foot Hellebore (H. foetidus), because they carry the flower buds formed in the previous growing season. If seedlings are not desired, remove old flowers before seed is set.
Propogation/Transplanting: Although plants may be slow to settle in, once they do, they rarely need division and may resent it. However, if necessary, large clumps of named cultivars and most species can be increased by division in early spring, although many professional growers prefer to divide Oriental hybrids (Helleborus × hybridus) in September. For best results, split clumps into several pieces with at least one growth point, and water well until they are established. The new divisions may be slow to establish, due to the lack of fine roots, and flowering may be poor in the following year, but they are likely to settle in given time.
Tips: Provide shelter from strong, cold winds.
The Christmas Rose (H. niger) may be slow to become established; to help it along, try a dose of magnesium in the form of Epsom salts or dolomitic limestone sprinkled around the plants. In summer pull out any unwanted new seedlings as hybrids may not come true from seed; move desirable species seedlings to permanent locations. Groom plants by removing yellow or dead leaves. Do not prune back for winter, but a light mulch of salt marsh hay may be beneficial.