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.
All species in the Helleborus genus hail from Eurasia and were first grown for their medicinal properties. They contain toxic alkaloids that make them deer-resistant but that also may be irritating to a gardener’s skin. Plants are rhizomatous and form clumps that are almost shrub-like. Leaves are lobed, often deeply, or fully divided into leaflets; some have leaves with markedly toothed margins. Foliage color ranges from deep green to pale grayish-green.
Hellebores are grown both for their foliage, which appears to be evergreen although individual stems die back annually, and for their bell-shaped flowers, some of which are upward facing, some downward, some flat, some much more cup-shaped. The colors range from purples to pinks to white and even yellow.
Plant hellebores in partial or dappled shade, in rich, well-draining soil amended with compost if the soil is poor. Although not fully drought tolerant, they do not need constant moisture and may be allowed dry periods in summer if located in enough shade. Protect them from strong, cold winds and mulch soil annually with compost.
Beautiful, lush leaves are always valued but not as much as the flowers that appear from December through March. Make sure to plant hellebores in a spot where flowers will be enjoyed, such as near a walkway or drive or where they can be seen from indoors.
Helleborus argutifolius (syn. H. corsicus). Corsican hellebore has dark green leaves with serrated margins and 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-seed but not aggressively and are easily pulled out.
Helleborus x hybridus. This group of hellebores contains hybrids of the rarely grown H. 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.
Helleborus foetidus. Unattractively called stinking hellebore, this species looks very different from the others. Deep green leaves are divided into many linear leaflets, creating a very lacey, graceful effect. Leaves do smell bad when crushed, but rarely is a smell noticeable. This species is a prolific bloomer with pale green flowers that stand above the leaf clusters and last for many weeks. The mature size is about 2 ft. x 18 in., although it can flop and sprawl a bit.
Helleborus x sternii. This cross between H. argutifolia and H. lividus has the robust characteristic of H. argutifolius with pinkish-purple leaf stalks and main veins, but is a bit smaller. It also has pinkish-purple highlights on its pale green flowers.
There are quite a few other species, all of which share the characteristics of winter bloom. Once established, they are relatively trouble-free, only needing to have their spent leaf and flower stalks cut away after bloom and to be top-dressed with compost in the fall. If aphids appear, some sharp squirts of water from the hose knock them off and they don’t come back.