| Helleborus The Genus The genus Helleborus covers a group of perennial plants from Europe and Asia. Virtually all are garden worthy, though the acaulescent (stemless) hybrids have become the most popular forms found in gardens. Helleborus is a small genus in the family Ranunculaceae, a wonderful collection of plants including many well-known garden plants. Hellebores are perhaps closest in relation to Caltha and Trollius, and the lesser known Megaleranthis. Eranthis has long been considered a close relative based on morphological similarities, but cytological evidence suggests that they are not so close at the molecular level. It is believed (based on research in China) that Eranthis may be closer allied to members of the tribe containing Cimicifuga and Actaea et al. Members of Ranunculaceae are mostly herbaceous with divided or lobed leaves. Leaves are generally basal or alternate on the stem. The color on the flowers mostly comes from the calyx, and most have five sepals. In Ranunculus, leaves may be undivided, and flowers have 'true' petals. In Clematis, sepals usually number four, and plants have opposite leaves and woody tissue. Hellebores generally have five sepals that persist in fruit around bisexual flower parts. The follicles may be separate or joined at the base. Within each carpel is more than one ovule. Leaves are divided into (sometimes many) leaflets which can be further subdivided into very fine segments, even less than one quarter of an inch in the case of Helleborus hercegovinus. Hellebores often produce large, leaf-like bracts and 'cauline' leaves along the flower stalks. Most have developed rhizomes and very short stems. Some have longer aerial stems and less developed rhizomes. In Cultivation Hellebores have a long history in cultivation, particularly in Europe. For centuries they have been used for various medical purposes, and all contain alkaloids and other chemicals that could lead to poisoning if ingested in large quantities. Hellebores are even mentioned in ancient Greek and Roman literature, but we can not be certain if the references are to the same plants that now carry the epithet associated with this genus. They have also been cultivated in western Europe and can be found naturalized around ruins of old monasteries and other structures. It is thus sometimes challenging to determine the native range and those colonies that may be escapes from old gardens. Extracts from hellebores have been used in homeopathy and traditional medicines in several countries. As a garden plant for active hybridizing, the older history is probably less certain, but much of the activity has occurred since around the middle of the twentieth century. In North America, hellebore popularity has grown markedly during the past decade, and now it is possible to find a variety of species and hybrids in nurseries and garden centers throughout North America. In fact, Helleborus x hybridus has been named the 2005 'Perennial Plant of the Year' by the Perennial Plant Association. Most hellebores are highly adaptable and will grow easily in many different environments. Sometimes referred to as 'Christmas Rose' or 'Lenten Rose', hellebores are the stars of the late winter/early spring garden. Plants generally bloom between December and March in cultivation, though some begin earlier, and others continue into April and May, particularly in gardens with colder spring climates. Nearly every garden has a spot for hellebores, and the plants will thrive in many different environments. Still, they remain unknown to many gardeners despite their toughness, beauty, hardiness, and wonderful habit of blooming in winter when most other plants remain dormant. The majority of hellebores are deep rooted, stout plants. Acaulescent hybrids (many, but not all, involving Helleborus orientalis) are well-known for their thick, shiny green foliage. The large leaves may persist through winter, but not all plants are wintergreen in all climates. Once established, most hellebores make drought- tolerant plants, particularly if given some dappled shade in areas of long, hot and/or dry summers. Yet, despite the fact hellebores are almost invariably sold as shade plants, in most garden conditions they will perform their best if given some sun. Many species grow wild in open meadows with only short grasses to shade the earth around them. Caulescent/Acaulescent Hellebores are separated into two main groups horticulturally. Simply put, the caulescent hellebores are those with (above-ground) stems and the acaulescent plants are those without visible above ground stems. Generally speaking, it is easiest to hybridize caulescent with caulescent and acaulescent with acaulescent, though there are exceptions. The Christmas rose (Helleborus niger) belongs in a category all its own. H. thibetanus and (particularly) H. vesicarius also exhibit unique qualities (see species page). There are even some 'acaulescent' plants that produce short above ground stems. A representative spectrum where plants are viewed in terms of 'caulescence' might include H. foetidus as the most caulescent and H. vesicarius as the least. H. niger would be somewhere in the middle. The caulescent/acaulescent model remains helpful and convenient for horticultural purposes. In addition to reproductive and morphological differences, one of the siginificant cultural differences between the two groups is that caulescent plants generally can not easily be subjected to division as a means of propagation. Acaulescent plants divide fairly easily, and this can be done in late spring or early autumn, or during summer in cooler climates. Caulescent plants generally are short lived. Often after three or four seasons the plants begin to fade in some gardens. However, they also mature much quicker on average, often blooming in their second spring. Older plants are easily replaced by younger seedlings. All hybrids between acaulescent plants are called Helleborus x hybridus. The caulescent hybrids are:
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Caulescent
Caulescent/acaulescent
Acaulescent
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