Dan Heims of Terra Nova Nurseries takes a seat at the table with DG writer Terri Lewin to answer your questions about the rapidly evolving and wildly popular world of Heucheras.
(Editor's Note: This article was originally published on October 4, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Heucheras, Historically: A Brief Introduction to the Genus
Heucheras (Coral Bells) have always been popular perennials, but they never seemed to be able to shake the image of being dependable (yet boring) "workhorse" plants. The early cultivated species and their hybrids took shade (often dry shade), they were reliably perennial in the cold zones of the northern U.S., and they don't require much maintenance such as frequent division. As a bonus, Heucheras are native to the United States and make an excellent non-invasive groundcover that is evergreen in most zones. Truly the type of plant most homeowners crave for difficult spots in the garden and one of the few true "plant it and forget it" plants.
This lovely shade bed features both Heuchera (front) and its close relative Tiarella (middle). The plant at back is a blue flowering Corydalis.
And it would have been forgotten, because there was one department where this wonder plant was lacking. It was an ugly duckling. The flowers on some species may best be described as "insignificant" and/or "sporadic". Most of the plants offered had bland green leaves lacking a distictive shape and certainly not contributing any notable texture to the landscape design. Early Heucheras served a function similar to that of rice served with a spicy meal: a bland but necessary scaffolding to the spicy show-stealers of the garden.
There was potential, though. Breeders and nursery owners began to sit up and take notice when they found a sport growing in their Heuchera stock. Eventually the sports and mutations of ornamental value were propagated and tested, and it didn't take long for gardeners to begin asking for certain hybrids by name. One of the early sucesses was the discovery of Heuchera 'Palace Purple' in the late eighties. H. 'Palace Purple'was discovered by Brian Halliwell of Kew Gardens, England, who named it to commemorate Kew Palace (a royal residence located within the Gardens). It was very distinctive for an early cultivar, sporting deep purple leaves with ruffled edges and rocketed to stardom as the Perennial Plant Association's Plant of the Year for 1991.
Around the same time and halfway around the world, Dan Heims was just starting up Terra Nova Nurseries when he came upon a chance variegated seedling of Heuchera sanguinea, which he named 'Snow Storm'. It could very well be argued that the first H. 'Snow Storm' and its subsequent propagation and sale was the catalyst for the re-examination of the genus' potential to be bred and sold the way it never was before. Since that initial re-awakening, Heuchera breeders have created plants that nobody would not have been thought possible just twenty five years ago. Almost every part of the plant has gained improvements in the looks department. Once restricted to choosing between green and olive-drab brown, the consumer now has a virtual palette of foliage color at their fingertips.
Leaf colors available include solid shocking lime green, blackish-purple, and intriguing shades of rich red-tinged brown. Names to look for at your local nursery include 'Caramel', a peachy leaved and heat tolerant Thierry Delabroye introduction and 'Silver Scrolls', which has dark purple leaves overlaid with silver. 'Silver Scrolls' is one of the many cultivars to be released out of the Primrose Path breeding program, and they believe it to be one of their best.
Many of the newer Heuchera cultivars are also surprisingly sun tolerant. Most will grow quite happily in part sun and a few will even tolerate full sun if adequately watered. Varieties with green leaves tend to prefer a shaded spot to prevent leaf burning whereas plants with purple, red, and peach tones will show their best color with a half day of sun. Heucheras aren't notoriously fussy about soil, but a site with good drainage is recommended.
A Conversation with Dan Heims, Heuchera Breeder and Expert
I have been a self-proclaimed "Heucherophile" for as long as I can remember. When I thought about what to cover for my first article on DG, there was no hesitiation on the topic, and no questions about who the "go-to man" in the world of Heucheras would be. Dan Heims is one of the founders of Terra Nova Nursery in Canby, Oregon and the co-author of Heucheras and Heucherellas: Coral Bells and Foamy Bells (Timber Press, 2005). Mr. Heims has over 20 years experience since he started the Heuchera breeding program at Terra Nova and is recognized widely in the horticultural community as an expert on Heucheras, Tiarellas, and the intergeneric x Heucherellas.
Terri Lewin- Hi Dan, and thanks for answering our questions. Your first success with Heucheras was the variegated cultivar 'Snow Storm' in 1988 while beginning "an intensive breeding effort in several relatively minor genera". Can you tell us a little bit about the challenges you faced early in your experience as a breeder and how you addressed them?
Dan Heims- Finding germplasm was difficult. You must remember, there was no internet back then. Photography was rare in catalogues. I had to depend on knowledge, Floras, the wonderful rock-garden society members. Once materials were in place, it came together.
T.L.- People have been using colchicine and radiation treatments since the 1940s to "encourage" new plant mutations and there are new techniques that allow us to select traits on the genetic level. Terra Nova has a "traditional breeder" on staff, as well as a breeder experienced in cytogenetics to manage the tissue culture lab along with other scientific considerations. From your perspective as a plant breeder, what do you think about genetic manipulation and do you have any opinions about how it will shape the production industry?
D.H.-GMOs are widely used in agriculture. We do none at Terra Nova. I like to say we breed the "old-fashioned way with the highest technology available." Tissue culture is only a way to do cuttings in mass quantities, it's not rocket science, but requires very clean, virus-free stock and sterile conditions at the early stages. I don't feel the public is ready for ornamental GMOs. But when the first true-blue rose is out, they may change their mind. People are already accepting genetically modified danios (zebra-fish) at the pet-shop level.
A few of the author's favorites. (L-R) Heuchera 'Mahogany'. H. 'Black Beauty', and H. 'Georgia Peach'
T.L.- Why is it near impossible to find Heucheras in pint pots at a local nursery?
D.H.- To grow a plant from seed, like Heuchera 'Palace Purple', the cost for a plantlet is pennies. Tissue culture IS expensive, but people are getting the most vigorous, garden-worthy, and interesting plants possible. These plugs cost several dollars at the lowest wholesale level and would probably produce a quart that would perhaps be a hard sell at about $10. Adding another 6 weeks will fill a gallon pot that consumers would feel more comfortable paying $19 for.
Frosty leaves on Heuchera 'Midnight Bayou'
T.L.- Several articles have suggested recently that incorporating Heuchera villosa into potential cultivars increases their heat tolerance. What cultivars can you recommend that can take on the challenge of basking through summer in the South?
D.H.- Both Heuchera villosa and Heuchera americana are natives of the hot and steamy southeastern U.S.. Fred Spicer of the Birmingham Botanic Garden showed me native stands of each in the wild areas of the garden. Both plants contribute heat/humidity tolerance to the hybrids. A visit to our website shows the USDA distribution maps and I go over the genetic makeup of each variety. Plants like 'Southern Comfort', 'Georgia Peach', 'Midnight Bayou', 'Electra' and 'Electric Lime' give a wide range of colors. Jimmy Turner of the Dallas Arboretum has done trials on many Terra Nova and Delabroye varieties. Heucherellas have done exceptionally well according to Jimmy. Varieties like 'Alabama Sunrise', 'Tapestry'. and 'Golden Zebra' all have H. villosa blood.
T.L.-Heuchera 'Midnight Rose' is a stunning mass of dark, almost black leaves speckled with hot pink. Some plants such as Abutilon 'Thompsonii' (flowering maple), some striped-petal roses, and Pelargonium 'White Mesh' have leaf and petal colouration induced by the presence of a virus that does not hurt the plant and is not transmissible. Is the spotting on 'Midnight Rose' the result of a "harmless" virus?
D.H.- Absolutely not! It is a breedable trait and is in fact, a chimera. It is truly variegated. Striped roses and Geraniums are the result of transposons, or "jumping genes" that can turn color on or off. Pelargonium 'Crocodile' and some of the marbled gold Abutilons like 'Thompsonii" (syn. pictum) ARE the result of a benign virus.
x Heucherella 'Sweet Tea' (left), H. 'Rave On' (middle), and H. 'Midnight Rose' (right)
T.L.- I've grown and overwintered Heucheras in large containers. They're a great perennial to use as a focal point planted with annuals, and they canstay in the container all year long for winter interest. What companion plants can you recommend that have similar requirements and will not overtake the slower growing Heuchera?
Heuchera may be kept in containers year-round, as pictured above
T.L.- I was lucky to see a sneak peak of x Heucherella 'Sweet Tea', which is slated for release in 2010. What else do we have to look forward to? Any heavy bloomers in the pipelines to steal the thunder from H. 'Rave On'?
D.H.- While 'Rave On' is hard to beat, look to any plants from our "Great Cities" collection like: 'Paris', 'Milan', 'Shanghai', and 'Havana'. All of these are reblooming machines, blooming from May till frost. All have compact form and beautiful leaves of silver, frosted green, and gold.
T.L.- You do a lot of travelling around the world in search of "new" plants that have not yet been introduced to culture in the United States. What has been your most exciting or rewarding discovery abroad? Anything that surprised you?
D.H.- I am lucky to enter a nursery in the U.S. and find something "new". Trips abroad bring me to collectors with astounding collections! I have been to a collector in Japan who only collected variegated Hepatica. A nursery in Tasmania that had numbers of frost-hardy plants from Cradle Mountain which I am sure many of you haven't seen. I am always surprised in Japan. They are some of the most avid plant-collectors I have ever met. My sensei, Dr.Yokoi, had several THOUSAND, different variegated plants in his garden and greenhouse. My biggest surprise: After traveling 60 miles through thickets of Sasa bamboo and Petasites, I arrived in Aomori prefecture. Arriving at a very modern nursery, I enquired as to whether a variegated form (chimeral-not that blotchy yellow thing) had ever been found. With a perfect inscrutable smile, my host motioned toward the lunchroom, where just that afternoon, an employee had brought in a stunning variegated form with 3-foot wide leaves of green, white, and lime green. I just about fainted!
Any good local nursery will carry at least a few cultivars. Heucheras are also widely available via mail order.
Dave's Garden offers two valuable resources for finding mail order sources of plants. Plant Scout allows you to search for sources by cultivar name, and Garden Watchdog provides customer reviews of mail order nurseries.
Terri has been working in the green industry since 2001. She was most recently at The Buffalo and Erie County Botanical Gardens in Buffalo, NY where she managed the propagation house, assisted in curatorial duties and acquisition and maintained three greenhouses for public display. She lives in Center City Philadelphia with her fiance.