Helleborus (Hellebore)

Hellebores are easy-to-grow perennials treasured in Sonoma County’s Mediterranean climate for a profusion of winter and early spring blooms that keep gardens flowering year-round. Their frost-hardy nature is especially valuable at a time of year when many other plants in the garden are just beginning to emerge or are still dormant.

Hellebores in Gardens

All species in the Helleborus genus hail from Eurasia and were first grown for their supposed medicinal properties or to ward off theoretical and invisible powers. All parts are poisonous.

• They contain toxic alkaloids that make them deer-resistant and irritating to a gardener’s skin.
• Plants are rhizomatous and form clumps; some are simply groups of stems while others are almost shrub-like, but all growth is succulent and never woody.
• Leaves are lobed, often deeply, or fully divided into fans or leaflets. Some species have leaves with markedly toothed margins.
• Foliage color ranges from deep green to pale grayish-green.
• Lush leaves are always valued as fillers in beds but flowers that appear singly or in clusters from December through March are more dramatic.
• Make sure to plant hellebores in a shaded or semi-shaded spot where flowers will be enjoyed, such as near a walkway or drive or where they can be easily viewed.
• Give them ample organic mix—compost is best—worked into garden beds with excellent drainage. Most species thrive on regular summer irrigation.

Growth Characteristics

Hellebores are valued for their bell-shaped flowers and their foliage, which appears to be evergreen although individual stems die back annually or every 2 yrs.

• Blossoms vary from species to species: some are upward facing, some downward, some flat, some much more cup-shaped.
• Flower colors range from purple to pink to white and even yellow. 
• On low-growing species, leaves appear to lack a true stem and grow up directly from the ground to about 1 ft. Taller types are about 2 ft. tall.
• Self-sowing is common, although seedlings may take 2 yrs. or more to mature. Closely spaced mature plants conceal open spaces as young plants slowly develop.

Low-Maintenance Plants

Although not fully drought-tolerant, most hellebores do not need constant moisture and may be allowed dry periods in summer if located in enough shade.

• Plant hellebores in partial or dappled shade, in rich, well-draining soil amended with compost if the soil is poor.
• Protect them from strong, cold winds.
• Once established, they are relatively trouble-free, only needing to have spent leaf and flower stalks removed in a timely fashion to maintain attractive appearance.
• Lightly work compost into the top 1-2 in. of beds in the fall and reapply mulch as needed.
• If aphids appear, a few sharp squirts of water from the hose knocks them off. 

Commonly Planted Hellebores

The following species are commonly sold in local nurseries, usually in late winter or early spring.

• Helleborus argutifolius (syn. Helleborus corsicus). Corsican hellebore has light to dark green leaves with serrated margins and robust, very pale green flower clusters in late winter and early spring. Plants stand 2½-3 ft. tall and as wide. Growth is lush and vigorous; plants self-sow but not aggressively and are easily pulled out if beds are crowded.
• Helleborus foetidus. Unattractively called stinking hellebore but also known as bear’s foot hellebore, this evergreen species looks very different from the others. Dark green leaves are divided into many linear leaflets, creating a mostly flat, very lacey, graceful effect. Leaves do smell bad when crushed, but odor is rarely noticeable. This species is a prolific bloomer with pale green flowers rising above leaf clusters and lasting for many weeks. The mature size is about 2 ft. x 18 in., although it can flop and sprawl a bit. It reseeds readily.
• Helleborus x hybridus. This group of hellebores contains hybrids of the rarely grown Helleborus orientalis crossed with other species. Typically they grow to about 18 in. high and wide and flower from mid-winter to mid-spring. Flowers are in shades of pink, purple, and yellow. New cultivars are frequently introduced.
• Helleborus niger and Helleborus orientalis are known as Christmas rose and Lenten rose but are often labeled interchangeably. They may actually be hybrid species since they hybridize easily and are often mistaken as hybrids.

August 2023