Sonoma County Master Gardeners Helping Sonoma Gardeners

When I wander around the garden at this time of year, I see that the vast majority of the plants have entered winter dormancy. The deciduous trees have shed their leaves, the ornamental grasses are brown and stiff, and the herbaceous ornamentals, by and large, have dead, dry tops with new life only apparent underneath at the soil level. The California natives tend to outshine most of their imported brethren in our winters, with some notable exceptions such as Hellebores.

I first encountered Hellebores when, long ago, I went looking for a plant that would flourish in dry shade. I kept coming up with various Hellebore species, so decided that they were worth a try. Now, years later, I have many different varieties in the garden, and find that they are generally easy to grow and dramatic at the time of year when most of the rest of the garden is muted or dormant.

Hellebores are of the genus Helleborus, members of the Ranuncula family, the same family that contains Buttercups, although the two plant groups could not look more different! Hellebores hail from Eurasia, and are frost hardy to fully hardy depending on the species, making them suitable for most Sonoma County gardens. They were first grown for their medicinal properties – they are full of alkaloids that have the bonus of allegedly make them deer-resistant! They are rhizomatous and either form clumps or are almost shrub-like. The leaves are either lobed, often deeply, or fully divided into leaflets. The foliage color ranges from deep green to pale grayish-green, and some have leaves with markedly toothed margins. They are effective grown in large clumps or interplanted with other perennials of similar size, such as Heuchera (Coral Bells), in a mixed border. They are grown primarily for their flowers, which are all bell-shaped, although some are upward facing, some downward; some flat, some much more cup-shaped. The colors range from purples to pinks to white and even yellow.

Plan to plant your Hellebores in rich, well-draining soil – amend your site with compost if the soil is poor – in partial or dappled shade. They are not fully ‘drought tolerant’ – you need to water them in summer – but they do not need to be kept wet all of the time. In fact, too-soggy soil is one thing that they really don’t like. Generally speaking, avoid the extremes – not too dry, not too wet, not too sunny and not deep shade. Protect them from strong, cold winds and mulch every autumn to get them ready for winter.

They will reward you with beautiful, lush leaves and lovely flowers! And they will produce the flowers any time from December through March, depending on the species. Make sure to plant them in a spot where you will be able to enjoy the flowers – near a walkway or drive, for example, or where you can see them from the inside of the house through a window. These ‘flowers’ are extremely long-lasting, because they are not actually flowers – what look like flowers to us are really the calyx of the plant – the ‘cup’ that surrounds the outside of the flower.

Varieties which grow well in Sonoma County and are generally readily available locally:

Helleborus argutifolia (syn. H. corsicus) – Corsican Hellebore – This species has dark green, serrated margin leaves with pale green flowers in late winter and early spring. The plants stand about 2 ½-3 ft tall, and about as wide. While it does not have the most dramatic flowers, Corsican Hellebore makes up for it by its vigorous growth habit and lush aspect. It self-seeds, but not aggressively.

Helleborus x hybridus – this group of Hellebores are all hybrids of H.orientalis and other species. Two that I have grown successfully without fuss are H. ‘Optimism’ and H. ‘Royal Heritage Strain’. The plants in this group generally have flowers in shades of pink, purple and yellow. I love to plant the purple-flowered ones, such as ‘Optimism’, next to purple-leaved Heuchera. These plants are generally smaller than Corsican Hellebore, typically about 18’’ by 18’’, and flower from mid-winter to mid-spring.

Helleborus foetidus –Unattractively called ‘Stinking Hellebore’, this species looks very different from the others. It has deeply toothed leaves, making a very lacey, graceful effect. The leaves do smell bad when crushed, but otherwise there is no problem with smell. The foliage is dark green with pale green flowers, and the plant is a prolific bloomer. At maturity it is about 3’ by 18’’, although it can flop and sprawl a bit. The flowers stand proud of the leaf clusters.

Helleborus x sternii – This is a cross between H. argutifolia and H. lividus, and has the robust characteristic of H. argutifolia with pinkish-purple leaf stalks and main veins. It also has pinkish-purple highlights on its pale green flowers. It is a bit smaller than H. argutifolia.

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 they bloom, and to be top-dressed with compost in the fall. I have had trouble with aphids (the H. Optimism gets attacked every fall by huge black ones) but some sharp squirts of water from the hose knock them off and they don’t come back.

Hellebores can be purchased locally at Sonoma Horticultural Nursery in Sebastopol (check winter hours), at Sonoma Mission Gardens in Sonoma, or ordered from specialty mail-order growers. If you want to read more about Hellebores, try ‘Hellebores: A Comprehensive Guide”, by C. Colston Burrell and Judith Knott Tyler, Timber Press 2006.

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