Growing hellebores in pots

Pine Knot Farms

Hellebores are very hardy and although most species will grow and thrive in Zones 4 through 9, we are not sure how well they would tolerate Zone 3 or Zone 10. We have customers who are growing our plants in 49 of the 50 states, everywhere but Hawaii! While many of the hellebore species have been grown in the US for a number of years the interspecies and intraspecies are fairly new to the gardening public and have not been thoroughly tested. These plants were very rare and available only to a select few ten years ago but are now sold in the millions thanks to micropropagation. While some vendors list H. x ericsmithii and H. x balardiae clones as hardy to zone 4 we are inclined to err on the side of caution listing them as zone 6. We’d rather a customer be surprised that a plant lives and thrives than disappointed that it died.

Although very tolerant of sunlignt, most hellebores prefer to grow in summer shade or partial shade in the warmer parts of the country, and do well on hillsides or sloping areas. When planting outside we recommend preparing the area beforehand if possible and improving drainage if needed. The plants also grow and display their flowers well in raised beds as long as the beds are deep enough to allow for at least eighteen inches (18”) of soil for rooting area for Lenten Roses. The interspecies hybrids H. foetidus and H. niger have shorter root systems and will grow quite well in containers. H. x hybridus, the Lenten Rose will also grow well but they must have large containers with lots of root space.

Helleborus x hybridus, true H. orientalis, H. niger, H. x nigercors, H. x ericsmithii, and H. foetidus, are evergreen, while H. argutifolius, H. lividus (tender), H. x sternii are evergreen in warmer climates, foliage can die back to ground level in colder areas. H. multifidus, H. purpurascens, H. viridis, H. odorus, H. atrorubens, H. dumetorum, H. cyclophyllus H. torquatus and H. croaticus are considered deciduous, although in some garden situations these may retain some foliage. Helleborus atrorubens is the first species to begin to go dormant in our garden, followed by H. thibetanus. In some areas (our Zone 7 garden among them) H. purpurascens and some strains of H. multifidus begin going dormant in August or September. Since buds are formed in summer, stress such as withholding food and water can reduce blooms in winter. When the nights begin to cool off a bit, in late August or early September, H. x hybridus plants begin to put on new leaves and seem to experience a growth spurt. We recommend cutting off flowers after seeds have ripened, and cutting back the old leaves of the evergreen species just before the flowers appear in winter to better appreciate the beautiful blooms.

GROWING HELLEBORES

Article by David Marks
Hellebores flower in winter to early spring and are small plants, easily missed at that time of year. So if you plan to grow some, and they are well worth it, be sure to plant them somewhere where they will be appreciated.

Ours are planted in a semi-shady spot near the back door so whenever I venture out into the garden in the chill of winter and early spring they can easily be appreciated. Another excellent place to grow them is by the borders of a path.

Corsican Hellebore

Use the checklist below to decide if Hellebores are suited to your needs and garden conditions

  • They do best in semi-shade.
  • They are fully hardy in all areas of the UK.
  • They grow well in most soils although avoid waterlogged or dry soils. Their preference is for a slightly alkaline soil but in truth they will grow alongside acid loving plants as well.
  • They will not withstand drought well. If their position is liable to dry out, water occasionally.
  • Hellebores are low maintenance plants. They benefit from a quick clear up in late autumn and on poor soils they will grow better with a twice yearly organic feed.
  • They are grown mainly for their flowers which appear from early January to mid-March.
  • There are pests and disease which affect hellebores but they are, on the whole, healthy plants.
  • Some are evergreen and some shed their leaves, it depends on the variety. They grow to a height and spread of 30cm / 1ft to 1m / 3ft depending on the variety.
  • Single flowered hellebores attract bees at a time of the year when little else does.
  • Hellebores are also frequently called Christmas Rose or Lenten Rose.

BEST CONDITIONS TO GROW HELLEBORES

Hellebores grow and flower best if they are are given as near as possible the same conditions as when they grow in the wild. The Germans call hellebores Schneerose which means “snow rose”, often more appropriate than the common English name of Christmas Rose. In fact, many hellebores don’t flower at Christmas, they prefer to wait until January in the UK, although some new varieties have been bred to be dependable Christmas bloomers.

They are most commonly found at the lower heights of mountains where the snow melts and easily drains away. Where they grow amongst trees, the trees are deciduous and shed their leaves in winter allowing the plants underneath to have lots of sunlight during winter and early spring.

From the above we recommend good draining ground, moisture at the roots, a sunny position during the winter months and dappled shade during the remainder of the year.

If you have a deep loam soil then that’s ideal. The next best soil is clay which has been improved with lots of well-rotted organic matter. Sandy soils are the least favourable although the addition of well-rotted organic matter can greatly improve your chances of growing quality hellebores.

DIFFERENT VARIETIES OF HELLEBORES

There are many varieties of hellebores and the number is increasing at a rapid rate as plant breeders produce new ones. In order to ensure that a hellebore grows true to type the plant growers need to isolate each variety and this makes them expensive to grow and of course, expensive to buy.

Combine that with their long life and it’s important to choose the best variety for your garden and preferences. Our guide to hellebore varieties aims to do just that, to go to that page.

WHERE AND WHEN TO BUY HELLEBORES

Breeding hellebores is very time-consuming and to end up with a decent variety takes significant skill. There are many low quality plants sold in the UK and they rarely turn out to be anything other than a disappointment. For that reason, stick to online names you know such as Crocus, RHS etc. Remember also, when comparing prices to take into account how large the plant is.

Seed grown hellebores can vary in colour. As a general rule, the cheaper the plant the more likely it is to be different from the parent. See our varieties page for hellebore series which are better than most. To get exactly the colour you want from a seed-grown hellebore you need to see it in flower. For this reason many nurseries only sell their plants when they are in flower – typically January to March.

If you select from one of the more reliable series where the colour will be very, very similar to the parent, it’s quite possible to buy hellebores in pots all the year through. Just ensure that for the first season they are watered in dry conditions.

One way to be 100% certain of getting an exact replica of the parent is to buy micro-propagated plants. These also are available all year round. Our recommendation would be Anna’s Red here, a stunning red-purple bloom, held high above the mottled, green leaves.

HOW AND WHEN TO PLANT A HELLEBORE

Hellebores can be planted at any time of the year. For some it’s most convenient to plant in late winter to early spring because that is when the majority are offered for sale. Follow the steps below:

  • Choose a position that is in part shade.
  • Choose a position which does not get water-logged. Improve drainage if necessary by adding a couple of spade fulls of well-rotted compost and horticultural grit to the soil when you plant the hellebore.
  • They have no preference for slightly acid or alkaline soils and will thrive in clay soils that are improved.
  • Dig a hole about 30cm / 12in deep and wide. Break up the soil incorporating any available compost. Add three handfuls of fish, blood and bone fertiliser (or bonemeal) to the dug soil and work it in.
  • Replace sufficient soil back in the hole so that when your hellebore is planted it will be to the same level as it was in the pot.
  • Place the roots in the hole and infill with the dug soil / compost / fertiliser. Firm the soil down around the roots reasonably firmly as you infill.
  • Water well if the ground is at all dry.

CARING FOR HELLEBORES

Hellebores will grow without any care at all as long as you keep the surrounding area weed-free. They are hungry plants though and will do better if fed with a good handful of fish, blood and bone fertiliser in March and then again September. Simply sprinkle the fertiliser around the plant and gently work it into the soil surface.

Hellebores can suffer from fungal diseases and the single best action you can take to avoid this is removing any dead or dying leaves in late November to December. This lets air circulate around the base of the plant and generally keeps them healthy, it’s also easier to see the flowers without a mass of dead leaves. As the the flowers die down in March / April cut the dead stems away for the same reason. Do not put any foliage or flowers on the compost heap.

PESTS AN DISEASES OF HELLEBORES

We list below some of the common pests and diseases which may affect your hellebore plants.

APHIDS

It’s a good idea to check your hellebores once a moth for aphids. Look on the underside of young leaves for white flecks (the shed skin of aphids) and the aphids themselves. Theses pests suck the sap and give out a sticky sweet liquid which attracts ants, fungi and diseases in general. See Hellebore Black Death below, aphids are thought to transmit this disease from plant to plant. for our page on treating aphids.

BLACK SPOT

This is most likely to affect plants of three or more years old. Black spots appear on leaves and as flower buds push through these are also marked black as will the blooms be when they emerge. Flower stems may wil and die. It is caused by the fungus Microsphaeropsis hellebori.

There are no fungicides specifically designed to treat Hellebore Black Spot but most plant fungicides will help control the problem. The best solution is to clear away all older leaves in November to December to stop the problem spreading and infecting new growth.

HELLEBORE BLACK DEATH

This is most likely to affect plants of three or more years old. The symptoms are blackened leaf veins, random black streaks on almost all parts of the plant. The disease is slow to progress and normally only kills the plant a year after the first symptoms.

Infected plants should be dug up and burnt. There is no treatment, chemical or otherwise. Aphids are thought to be the mechanism that transmits the infection. Although this disease has a dramatic name it rarely affects hellebores in the average garden, it is more likely to be a problem in massed plantings and at plant nurseries.

SLUGS AND SNAILS

Fully grown hellebores can have their flowers eaten by slugs and snails but it’s not common. Much more likely is that tender young seedlings are eaten. The best cure is to keep the seedlings in pots away from slugs and snails. Plant out when they are a year or so old and less likely to be damaged.

GROWING HELLEBORES IN CONTAINERS / POTS

You might not think it, given their relatively small size but hellebores do best when their roots are allowed to go down deep – width is not so important. if you plant a hellebore in a container start them off in a pot 40cm / 16in deep or more and then re-pot every two years into a pot 5cm / 2in deeper. When the pot depth reaches 60cm / 2ft that should be sufficient.

Not to get to dreamy eyed, but a hellebore in a pot / container placed near where you pass it frequently is a real delight. The height of the pot makes the plants more visible and it can be positioned to give the very best conditions. Full sun in winter and spring, then partial shade for the rest of the year.

Use John Innes compost and horticultural girt in the pot with a layer of stones at the base to provide drainage. You will need to keep the pot watered but with a relatively large one that is not too difficult. A twice yearly feed with a large handful of fish, blood and bone twice a year in March and September will provide all the nutrients your hellebore needs and it’s organic.

HELLEBORE SUMMARY

Below we list the key strengths and weaknesses of Hellebores.

HARDY (to -20°C)
CLAY SOIL Yes but not water-logged
SANDY SOIL Yes if improved
DRY SOIL No
SHADE No, partial shade is best although they will tolerate full sun
EVERGREEN Yes
EASY CARE
SMALL GARDENS Yes
POT / CONTAINER Yes
FLOWERING
FLOWER TIME Late January to mid March

Other “easy-care” shrubs in this series include Choisya, Hebes, Skimmia, Lilacs, Potentilla and Rose of Sharon (hibiscus syriacus).

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Hellebores

Hellebores sound like a dream come true. They really do bloom when the garden looks wintry and the ground is still dotted with the last traces of snow. The flowers are big, bold and abundant, and they come in several colors–pinks, purples, dusky reds, white, pale green and even some yellows. And their color range keeps expanding as plant breeders give more attention to these up-and-coming perennials. What’s more, hellebores are shade lovers, which is good news for maturing gardens. Perhaps most impressive of all, however, is that the foliage of most kinds of hellebores is attractive year-round. No wonder knowledgeable plantsmen rank hellebores among the top 10 high-performance perennials.

It’s not just that flowers of hellebores come so early that makes them appealing to gardeners: They stay awhile as well. Because the buds begin to emerge during very cool weather and the whole process occurs slowly, the display can go on for months. Individual blossoms can range in size from an inch to three inches across (depending on the species) and are shaped like giant buttercups, to which they are related.

What sets hellebores above most other perennials, though, is their striking foliage, which looks good year-round in most locations. I hear that the leaves are even able to come through hailstorms in good condition. The foliage of most kinds is leathery and a beautiful deep green. Individual leaves are deeply divided and “palmate”, which means they are shaped roughly like a very large hand spread wide. They might remind you of mayapple or of pachysandra.

Hellebore foliage combines well with other shade-loving perennials like wild ginger (Asarum), cyclamen or Pulmonaria, as well as with bulbs such as snowdrops or miniature daffodils. Plant these combinations under open shrubs or trees with high shade. Serious ground covers like vinca, pachysandra or ivy are too aggressive to make good companions. An established clump of hellebores will cover a patch of ground quite effectively, but the plants spread so slowly and are so expensive that they can’t be rightly classed among classic ground-cover plants.

Individual hellebore plants are long-lived. They don’t ever need dividing and, in fact, they recover slowly from any root disturbance. Division is a very slow way to propagate hellebores (some can’t be divided), which is one reason the plants are still fairly uncommon in garden centers. Even many mail-order catalogs offer only one or two kinds. Hellebores do grow quite readily from seed, however. The easiest way to get more plants is to move the seedlings that will begin to appear around the base of established plants.

The Best Hellebores

There are 20 or so hellebore species. Most come from countries on the northern rim of the Mediterranean, especially in the Balkan Peninsula and into the Caucasian Mountains. Plant collectors are busy experimenting with and hybridizing these species. For gardeners, though, the four kinds described in detail here are the most widely adaptable and easiest to grow.

All hellebores fall into two very distinct groups. Plants of one kind have a stalk that holds leaves, ending in flower buds at the top. This type can’t be propagated by division. The plant gets larger by making new stalks that arise just above ground level from the first stem that formed, which becomes like a crown. All stems flower at the end of their second winter. It’s best to cut them back close to the base of the plant after the seeds have matured (or earlier if you don’t want seedlings). Mature plants may have six or eight stems at a given time.

The other kind, which can be divided, sends up individual leaves and flower stalks separately from rhizomes underground. Each leaf and each flower cluster has its own stem. The plants get bigger as the rhizomes branch and spread. Some gardeners remove any foliage that has become tattered or weather-worn late in winter just before the flower st emerge. New leaves emerge soon after. This group of hellebores also self-sows generously in moist humus-rich soil.

Hellebores are often classified as shade-loving plants, and they thrive with some protection from the hottest sun of the day in summer. The more dependable the water supply, the more sun they can take. In nature, they often grow among tall grasses, perennials or in hedgerows where the taller plants provide summer shade. Take this cue and plant them among tall perennials in sunny borders or with ornamental grasses. While hellebores grow in a wide range of garden soils, they do best in a neutral to slightly alkaline environment.

Helleborus argutifolius (Corsican hellebore). Best for southern California, this species tolerates more sun and drier conditions than other hellebores. Stems grow from the basal crown and get two to three feet tall, topped with large clusters of pale green nodding flowers in late winter and early spring. Mature plants can be three feet across. The large leaves are a handsome blue-green. The plant is hardy through zone 6, but the leaves can suffer winter damage even in northern zone 8.

H. foetidus (stinking hellebore). This is one of the hardiest and most versatile of all hellebores. It gets its name because crushed leaves, stems and sometimes flowers emit a strange, catlike odor. It is widely adapted, growing in hardiness zones 5 to 9, and is an excellent choice for dry shade. The dark green leaves have four to nine narrow leaflets. Individual stalks get about two feet tall, and mature plants spread three feet across. The flowers appear in large clusters at the top of the stalks. Each one is pale green, occasionally edged with purple and about an inch across. The buds begin to appear in early winter and provide interest as they open slowly over the next three months.

H. niger (Christmas rose). Native to the mountains of Europe, this species needs some winter cold to really thrive, so it grows best in zones 3 to 8 in the U.S. It prefers light shade and moist, slightly alkaline soil. Typically, it flowers in late winter, sometimes even later than its cousin the Lenten rose. Evergreen leaves, which grow from rhizomes, often suffer winter damage. The flowers (one to three per stem) are a pure white that ages into rose.

H. orientalis (Lenten rose). These hellebores, which are almost always hybrids, are the best choice for most gardeners. They are hardy from zones 4 to 9, and their leaves take winter cold better than H. niger. The flowers come in the widest range of colors (white through pink, purple to yellow, as well as mottled bicolors), and they look good for a full two months. The Lenten rose is the easiest of all hellebores to transplant, and a single plant will spread quickly. It also self-sows quite readily.

Jack Ruttle is a former senior editor at National Gardening.

Photography by Suzanne DeJohn/National Gardening Association

Growing Hellebore In Containers – How To Care For Hellebores In A Pot

Hellebore is a lovely and unique flowering perennial that adds blooms and color to gardens in early spring, or depending on the climate, in late winter. More often used in beds, potted hellebores can also be a nice addition to patios and indoor areas.

Can You Grow a Hellebore in a Container?

Hellebore plants are prized for their unusual and pretty flowers, but also because the blooms come out in winter or early spring. These are great plants for four-season gardens and if you need something to add winter color to your beds. But what about hellebore in containers? You absolutely can grow these plants in containers, but there are some important things to keep in mind in order to help them thrive in pots.

How to Care for Hellebores in a Pot

You may see container grown hellebore around Christmas time when it is sold as Christmas rose. Often these, along with other holiday plants like poinsettia, are used for decorations and then allowed to die or just tossed. There’s no need to let your potted hellebore go downhill, though. You can keep it potted until you’re ready to put it in the ground outside, or you can keep it potted and enjoy it indoors and out, year round.

Hellebore needs rich and well-drained soil, so be sure to choose a pot that drains and use a rich organic potting soil or add compost to existing soil. It’s also important to choose a large container, as hellebore plants don’t like to be transferred. The stress of the move can be damaging, so give your plant room to grow. The depth of the pot is particularly important as the roots mostly grow down.

Position your potted hellebores to get as much sun as possible during the winter and spring months. A little shade will be appreciated as it gets warmer. Hellebore also prefers cooler temperatures in the winter, so make sure it gets sun without too much heat. The flowers tend to droop downward, so find an elevated position for your container grown hellebore so you can fully enjoy it.

Hellebore is at its best when planted outdoors in the ground, but if you have limited space or you simply want to enjoy these lovely flowers as a houseplant, you should be able to make it comfortable in an indoor container.

A wonderful sight in the bleak mid-winter

Black spot

Pot-grown Christmas roses also escape black spot – Coniothyrium hellebori – which can be a big problem for them. The disease commonly affects all hellebore foliage and occurs when water-borne spores travel between the blackened leaves and the ground – and back again. Pot-grown hellebores, raised well above soil level, do not suffer in the same way.

To prevent the spread of black spot always take off the top inch of soil from newly bought hellebores, even if they look healthy, and replace it with fresh compost. This will remove any troublesome spores that may be lingering in the pot. Nursery stock is invariably sprayed, but you shouldn’t need to do this if you follow this regime. Remove leaves that show signs of the disease whenever you see them and take off every leaf in early December, so that only the emerging buds are left.

Forcing Christmas roses

Resourceful Victorian head gardeners lifted entire plants of Helleborus niger in September and brought them under glass to force them into flower for December 25. Despite their name, Christmas roses usually wait until the new year to flower. The big danger of growing any hellebore in a greenhouse during our damp winters is botrytis. This grey mould appears when the air- flow is restricted, so make sure that you ventilate your glasshouse or cold frame daily.

Potting young Christmas roses

By now, garden centres and nurseries will have plenty of young, seed-raised plants for sale. Once bought and taken home, examine the foliage carefully and remove all dead, blackened or yellow leaves (1), leaving the healthy leaves intact.

Be sure to examine the root system. A healthy plant will have an unbroken network of thick white roots. If the root system is poor, loosen the soil to check for vine-weevil grubs.

Fill a deep rose pot to within 5in of the top using a mix of one third coarse grit to two-thirds soil-based compost (John Innes No 3 is ideal for these greedy feeders) (2). Place the hellebore on top of the soil and fill round the plant (3), adding a top-dressing of coarse grit (4). This and the gritty compost will help to deter vine weevils from attacking the roots and improve drainage.

Place your pots in the lee of a house for a few weeks to avoid waterlogging by winter rain.

Dead-heading

Newly rooted young plants should flower the following winter. Be sure to dead-head the faded flowers, which turn a pale-pink colour as they age, to encourage an unbroken succession of blooms. All the hellobore’s energy needs to go into producing a strong plant, not into seeds.

Repotting mature Christmas roses

After flowering, place the plants in a cold frame or somewhere out of full sun in your garden. Keep them just moist during very dry summers, giving them a dormant period. Take them out of the frame in September and check the leaves, removing any chlorotic (yellow) or diseased leaves. Upend the plants and check the root system again: by now the roots should be at the edge of the pot. Using a half grit and half soil-based compost mixture transfer them into a slightly larger pot. Add another layer of grit to deter weevil damage.

Planting companions

Large pots of Christmas roses look as good as single specimens and do well throughout the winter placed against any door, regardless of aspect.

Mixed containers look most effective if they include one Christmas rose mixed with the glossy leaves of ivies, evergreen euonymus and varieties of Skimmia japonica. Deep-red outdoor cyclamen look particularly gorgeous with the white flowers.

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