Helleborus are tough versatile plants, whose preferred conditions are neutral to alkaline soil with dappled shade, but will tolerate a wide range of growing conditions excluding only very wet or dry conditions. This means Hellebores are plants you can place in most parts of the garden. Hellebores are quite vigorous and multiple quickly to make larger clumps. Which means when planting give them room to expand.
Hellebores flower from December through to mid-spring, although the flowers may stay on the plants longer as they slowly fade, but still look attractive. Many Hellebores are self seeders, (although not all the modern hybrids which do not always produce seed.) If you want to restrict the spread of Hellebores, remove the spent flower heads. When self seed the new seedlings will form a clump near the parent plant which will flower after two or three years, a process which over time creates clumps of Hellebores( image above left) which look good in a natural or woodland setting. There are some early flowering varieties which look good in December, (image bottom right H. "Christmas Carol") and in tubs to create a winter bedding scheme.
Hellebores are reliable and flower every year once established with little or no attention. Most are very hardy, H5 which is -15 -10.
Hellebores require little or no maintenance, but they do better if the old foliage is removed in late winter during January. Removal of most or all of the foliage serves several purposes. First, it displays the flowers at their best, leaving just the new young foliage coming through. When you cut back you will need to do so carefully as at ground level the flowers are in bud forming along with new foliage. In some professional gardens such as the RHS all the old foliage is removed to show off the flowers.
The second reason is that Hellebores are prone to black spot, and by Dec/Jan the leaves can have evidence of black spot to a greater and lesser degree. In 2017/2018 we suffered a very wet winter as a result I cut all the leaves from the Hellebores to remove the black spot infestation.
Leaves are required for photosynthesis, but they can be removed in the Winter and new foliage will grow ready for the spring ready for photosynthesis. As a woodland plant an ideal mulch is leaf mould, (image below right) although any well-rotted organic matter will be suitable.
Most Helleborus are fully hardy and will grow reliably year after year. Some Helleborus × hybridus are borderline, which means they may need winter protection, especially in more exposed gardens.
Hellebores are good for under planting deciduous shrubs.