Understanding Helleborus

The explosion in helleborus breeding has resulted in many colors and flower types.

Hellebores (Helleborus spp.) have been horticulture’s hot stock for the last few years and every year there are more introductions on the market. While many hellebores are long-lived, drought- and pest-resistant perennials suitable for most of our large country, it is important to note that there are several types of hellebores on the market today. There are different species of hellebores, as well as hybrid crosses, each with diverse attributes and distinct cultural requirements. Because each species has different advantages and traits, it is important to understand a bit of the botany to successfully grow and sell hellebores.

Lenten Roses Are The Most Common
The most commonly grown hellebores, Lenten roses, have been available at garden centers for many years. The Lenten rose types were called Helleborus orientalis, which was changed to H. ×orientalis and later to H. ×hybridus. This was supposedly to show that the group is composed of hybrids from several other species, as well as H. orientalis, although sometimes it seems the name changes were done just to confuse us.

The Lenten rose types are almost always produced from seed, and plants are sold as mixed color strains or color groups. Seedlings are variable and should not be sold as clones. The plants require a couple of years after transplanting to reach blooming size. Mature plants can easily reach 36 inches in diameter and nearly that in height as the flower stems appear in late winter.

Although generally regarded as shade plants, the Lenten rose types will tolerate a wide range of growing conditions including full sun in northern regions. This hellebore has a very deep root system, and plants are extremely drought tolerant once established. Winter-damaged foliage may be completely removed before the flowering stems emerge without affecting the plant.

H. ×hybridus has been difficult to micro propagate, and plant numbers are slow to bulk up. There are tissue culture clones available as young plants from the Heuger Company in Germany (as the Spring Promise Series). As the labs refine their techniques, we will see more clones in the coming years. Until that time, we feel the best of the by-color seed strains are the Winter Jewels series from Ernie and Marietta O’Byrne.

Christmas Rose Is A Smaller Species
H. niger, the white-flowering Christmas rose, is valued for its winter blooms and is one of the smaller species. It produces 8- to 14-inch-tall flower stems over plants that slowly expand to approximately 24 inches wide. The plants have quite shallow root systems and do not like to have all of their foliage removed at one time.

This species is easy to micropropagate, and there are several tissue culture clones on the market. H. niger is fertile and seed strains are available, but like all hellebores, the seedling offspring will be variable and should not be sold under the clonal name.

Heuger has introduced clones of H. niger sold as the Heuger Gold Collection. Some of them are H. niger ‘HGC Jacob,’ ‘HGC Joshua’ and one we think is the best of the lot: H. niger ‘HGC Joseph Lempur.’ One advantage of clonal production is being able to produce a group of identical plants, which allows them all to flower at the same time. This is especially nice for plants grown as a pot crop, as you can count on a big block of color for a particular sales period.

Interspecies And Intersectional Hybrids Are Newer Forms
Joining the Christmas and Lenten roses at garden centers is an unusual group known as the interspecies or intersectional hybrids. This group doesn’t appear to have a user-friendly common name yet, but it won’t be long before they are being called something catchy like holiday roses. These newer forms, Helleborus ×ballardiae, H. ×ericsmithii and H. ×nigercors, are seedling crosses. This means they are hybrids between at least two different species that have attributes from each.

One of the parents of all three groups is H. niger. The other parents are H. lividus for the ballardiae group, H. argutifolius for the nigercors group and H. ×sternii for the ericsmithii group. We haven’t found a way to simplify this bit; if you feel a bit overwhelmed, so did we when we first began to breed these plants. In fact, we had to make myself a cheat sheet. we wrote down all the crosses on a piece of paper to keep in my pocket. These hybrids are increased by micropropagation because they are almost always sterile.

Attesting to their H. niger parentage, the new clones open white or cream with flowers that face outward at about 90 degrees. This is the feature most often lauded in the popular press, sometimes referred to as “upward facing.” As the blossoms mature, they go through a series of color changes; the degree and shade of pink varies from clone to clone.

Helleborus lividus is a tender perennial. We cannot grow it outside in our Zone 7 garden. This plant is the pollen parent to H. ×ballardiae and is part of the background for H. ×sternii. It produces dusky pink blossoms and gives its color to many of the new plants.

H. ×nigercors usually opens white and ages to green. As with other hellebores, the deeper colors seem to be more prevalent with cooler temperatures. The foliage can be very different on individual clones; some are heavily veined while others have silvery or bluish-green leaves. Interspecies hybrids resemble H. niger in culture and also do not like a complete “winter haircut.” They have shallow root systems and grow happily in containers. Plants grow well in sun or shade, except in the South where afternoon shade is appreciated.

Cold Hardiness Still Needs To Be Tested
We do not feel that the interspecies or intersectional hybrids have been available in this country long enough to guarantee their hardiness. The plant labels that accompany plugs give hardiness as -20ºF or -30ºF, but personally we would offer a caution.

A plant may survive these low temperatures if there is good snow cover, but in the Midwest, with the wind whistling down the plains and no snow cover some question remains. These hybrids make wonderful container plants that can remain outside year round with a minimal amount of protection during very cold periods. Although helleborus plants may be hardy outside, it is important to remember and remind buyers that if plants have been grown in even minimally heated houses, they will not tolerate being moved outside into subfreezing temperatures after the holidays. These plants must be kept indoors and gradually hardened off before they can be moved outside.

We have barely scratched the surface of the hellebore tribe, leaving more species and even newer hybrids for another day. If the past few years are any indication, it seems there will be a hellebore for every application. Try some this year and see what everyone is talking about.

Richard E. Tyler and Judith Knott Tyler ([email protected]) are co-owners of Pine Knot Farm in Clarksville, Va. They are avid and well-known collectors and breeders of hellebores, and their breeding work with the double forms of helleborus has sparked national interest. 

 

Leave a Reply

5 comments on “Understanding Helleborus

  1. There are several references to “I” and “we” in this article, but I don’t see a specific author listed. Who wrote this piece?

  2. Hi Paul — Good catch. Richard Tyler and Judith Knott Tyler, co-owners of Pine Knot Farm, are the authors. Their information is now listed. Thanks for reading!

    1. Knowing the Tylers wrote this piece raises the credibility for me. They (with Cole) literally wrote the book! Thanks, Sara 🙂

  3. Should I cover Hellebore blossoms when a cold spell of low 20’s are predicted in the Northeast in the next couple days

More From Varieties...
Suntory Grandessa argyranthemum - feature

September 18, 2017

Breeders Open Availability for Unrooted Cuttings; Here’s How Growers Will Benefit

With new avenues for buying young plants for vegetative production, growers should have an easier time finding availability and receiving shipments of unrooted cuttings for the coming seasons.

Read More
Ball, Tagawa Succulents Partnership

September 14, 2017

Ball Seed to Partner With Tagawa Greenhouses on New Succulent Offerings

The new program includes in-demand retail products that are popular with younger shoppers, allowing growers to easily build a comprehensive succulent program and stay on-trend in the marketplace.

Read More
Strait-Laced Elderberry

September 10, 2017

Check Out the Top Varieties On Display at Farwest 2017

A panel of plant experts, along with show attendees, selected their favorite offerings during the Farwest 2017 New Varieties Showcase.

Read More
Latest Stories
Suntory Grandessa argyranthemum - feature

September 18, 2017

Breeders Open Availability for Unrooted Cuttings; Here&…

With new avenues for buying young plants for vegetative production, growers should have an easier time finding availability and receiving shipments of unrooted cuttings for the coming seasons.

Read More
Ball, Tagawa Succulents Partnership

September 14, 2017

Ball Seed to Partner With Tagawa Greenhouses on New Suc…

The new program includes in-demand retail products that are popular with younger shoppers, allowing growers to easily build a comprehensive succulent program and stay on-trend in the marketplace.

Read More
Strait-Laced Elderberry

September 10, 2017

Check Out the Top Varieties On Display at Farwest 2017

A panel of plant experts, along with show attendees, selected their favorite offerings during the Farwest 2017 New Varieties Showcase.

Read More

September 5, 2017

Hort Couture Announces New Propagation and Broker Partn…

The new grower-propagator partners are deeply vested in the independent garden center channel with propagation expertise, as well as finished production focused on the independent grower.

Read More
Helianthus Sunfinity (Syngenta Flowers)

September 3, 2017

Growing Tips for Helianthus Sunflower ‘Sunfinity…

This annual sunflower is a profuse bloomer with strong branching that produces multiple flowers per plant from spring to fall.

Read More
Ball Seed Field Day 2017

September 2, 2017

Highlights from Ball Seed’s Annual Field Day and Landsc…

Attendees of the one-day event had the opportunity to see new plants in up-close-and-personal trials, and engage with speakers and product experts.

Read More
Bidens Popstar (Kientzler)

August 31, 2017

Allan Armitage: Why I’ve Become a Fan of Bidens

The rather boring plant with mundane daisy-yellow flowers has morphed into a vigorous plant carrying colorful flowers that seems to be comfortable in most of the country.

Read More

August 29, 2017

27 New Impatiens for Spring Color in 2018

Gardeners love impatiens because they are one of the few plants that offer stand-out, splashy blooms for shady areas, and in some cases full sun. There's no shortage of new introductions this year to choose from for your 2018 product mix. Here are 27 new and improved varieties to consider offering to your customers.  

Read More
Calandiva kalanchoes (Dümmen Orange) Feature

August 28, 2017

Lifestyle Plants Are in Full Bloom for Consumers

The latest decorating trends indicate consumers want hassle-free, colorful plants with big flowers — and growers are finding unique ways to cash in on these luxury-item sales.

Read More
Cuphea Fairy Dust Pink (Proven Winners) feature

August 26, 2017

Kelly Norris: Noteworthy Plants That Caught My Attentio…

Imagine the modern consumer getting so excited about a new plant that they shared the experience with a friend, perhaps not even a fellow gardening consumer.

Read More

August 20, 2017

Proven Winners and Kentucky Nursery and Landscape Assoc…

This year, KNLA is combining its summer outing with the Proven Winners Landscape Roadshow for an informative event that will take place on September 21.

Read More
Four Star 2018 Catalog

August 18, 2017

Four Star Greenhouses’ 2018 Catalog Includes New Variet…

The new catalog is available in both print and digital formats, and features information on new trays that allow for more plugs per square foot.

Read More
Francis Kwong, PanAmerican Seed

August 15, 2017

Ornamental Seed Scientist Francis Kwong Dies at Age 65

Kwong was most recently the Director of Seed Technology for PanAmerican Seed, and his research was instrumental in the development of calibrachoa, angelonia, and other plants.

Read More
Candy Tops Snapdragons Series (Sakata Ornamentals)

August 3, 2017

Five Characteristics Breeders Want in Top-Performing Sp…

New spring annuals have to provide something for everyone — longevity, durability, performance, and more — if they want to meet breeders’ high standards for market-worthy plants.

Read More
Petunia 'Headliner Pink Sky" (Selecta)

August 3, 2017

Why Eccentricity is the New Black in Spring Annuals

Consumers judge plants by appearance, color impact, and ease of maintenance, which is why retailers want new spring annuals that are novel standouts.    

Read More

August 1, 2017

39 New Vegetables and Herbs for 2018

New vegetable and herb introductions for 2017 offer unique shaped fruits, distinctive foliage, intense flavors, improved disease resistance, high yields, and more. Here are 39 new vegetable and herb varieties to consider for your product mix in 2018.

Read More
2018 Griffin Catalog

July 31, 2017

Griffin Releases Print and Digital Versions of Its 2018…

The 250-page print catalog features more than 350 new varieties from leading breeders, while the enhanced digital version has extra features on crop culture, grower tools, and more.

Read More
Emerald-Coast-Growers-Guide-Feature-Image

July 27, 2017

Emerald Coast Growers Offers Updated Guide on its Newes…

This year’s guide features new varieties while maintaining Emerald Coast’s ornamental grass program and expanding its perennial plants line.

Read More