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  The American Gardener
 
 


January/February 2002

Members Forum

PRUNING GINKGOs

In response to the question about pruning ginkgos that was published in the Gardeners Information Service page in the September/October issue, I would like to contribute more information about keeping a ginkgo dwarf, or at least shorter than normal.

In my rock garden I have a 25-year-old ginkgo that is 41/2 feet wide and 21/2 feet tall. The trunk is five inches in diameter. When the original plant was eight inches high, I began heading it back to create a multi-branch growth pattern. Keeping in mind the need to keep a fairly balanced overall shape, whenever a new stem develops four or five leaves, I then cut it back to one, two, or three leaves. When the plant is dormant, I also thin it out by removing branches at the site of origin.

My ginkgo specimen is now a multi-twigged plant and quite attractive. It is very healthy and never fed. When visitors ask if the plant has a name, I tell them it is a “secateur dwarf.” I believe this technique can be successfully used to keep many woody plants small, but the larger the plant is when the pruning process is started, the more labor-intensive it will be.

Planted near the ginkgo is a 40-year-old Enkianthus perulatus var. compactus. In contrast to the ginkgo, this compact shrub—less than two feet tall and four feet in diameter—has never had to be pruned.

Nickolas Nickou - Branford, Connecticut

 

HELLEBORES REDUX

Editor’s Note: In testament to the passion inspired by hellebores, we received several letters in response to a request by Norman Deno in our September/October issue for information concerning forms of Helleborus orientalis with superior flower colors and whether there are forms of Helleborus niger that bloom in fall. A selection of the letters is printed below.

I would like to say thank you, along with a round of applause, to Mr. Deno for his research and publications on seed germination. His work is very much appreciated by those of us who grow our own plants from seed.

As Colston Burrell pointed out in his article on hellebores in The American Gardener last year (January/February), when discussing H. orientalis we first need to make sure we are speaking of the same plant. Hellebores sold with the name H. orientalis are for the most part garden hybrids that should more correctly be called H. 5hybridus. Will McLewin, a British hellebore expert, has been advocating this nomenclature for some time. What is carried in the nursery trade as H. orientalis has long since lost most or all of its resemblance to the species.

The true species H. orientalis is coming back into the trade as interest grows in hellebores in England, Germany, Australia and here in America. In a few collectors catalogs you will now find both H. 5hybridus and H. orientalis along with color selections of each due to the numerous breeding programs being conducted today. There are good color forms of each available, so I would suggest a trip to the library to browse any of the books specializing in hellebores currently on the market. All provide a wealth of color photos and information. A favorite of mine is The Gardener’s Guide to Growing Hellebores by Graham Rice and Elizabeth Strangman, published by Timber Press.

Plants and seeds of good color forms of H. 5hybridus and H. orientalis are available commercially. In addition to the sources listed in Burrell’s article, McLewin sells seeds from his collecting expeditions and his garden where his breeding program takes place. Helen Ballard also offers many of the better color forms from her breeding programs. Often individual collectors and growers are quite easily located and contacted through the Internet.

The Christmas rose (H. niger) sets buds above ground toward the end of January here in southern Indiana, but no real bloom occurs until the latter part of February and into March. The number, timing, and quality of flowers is very much weather dependant. Dormant buds replace flowers damaged by hard freezes and lack of snow cover, but there is always a show to some degree.

If Mr. Deno saw H. niger blooming in November, it was more than likely a different strain than the one currently on the mass market. A strain of early-winter blooming H. niger was in circulation some years ago but seemed to have somehow gotten lost in the trade for a while. Of late, fortunately, that particular strain seems to be more readily available once again. I have H. niger in three locations in my garden. Two were planted in quite poor locations back when I was a novice gardener. I feel the reputation H. niger has gained for being a bit of a problem is more myth than actual gardening experience.

Gene Bush - Depauw, Indiana

Editor’s Note: Formerly a chemistry professor at the Pennsylvania State University in State College, Deno is best known in gardening circles for his research on seed germination requirements. He has self-published three references on seed germination, beginning with Seed Germination Theory and Practice in 1993. For information about his publications, send a stamped, self-addressed envelope to Norman Deno, 139 Lenor Drive, State College, PA 16801.

Of the various hellebores that I have tried in my Zone 7 Piedmont garden, H. niger has been the most challenging. While it did not perform for me at all, in a friend’s garden just 12 miles away, a single specimen planted some five years ago has now become a large, shrublike species some two feet in diameter producing some 30 blooms yearly. This plant invariably blooms at Christmas time, its first flower generally opening on Christmas Day. Frustrated at my failure, I finally consulted Don Jacobs of Eco Gardens in Decatur, Georgia, who grows and offers a variety of hellebore species and selections. According to him, H. niger does not tolerate acid soil. While hellebores such as H. orientalis, H. foetidus, and H. argutifolius will tolerate generally acidic soils and grow well, as they have for me, H. niger will do so only with the addition of generous quantities of lime.

I should also mention that some lovely selections of H. 5hybridus are available from Jacobs, among them a lovely pink, ‘Eco Frosted Plum’, which has continued to increase in size and bloom regularly from the first year I planted it.

Two good resources on hellebores are:

Hellebores by Brian F. Mathew, published by the Alpine Garden Society, Woking, 1989.

A scholarly and fascinating six-part study on hellebores by Will McLewin and Brian Mathew was published in The New Plantsman from 1996 to 1998. There is also a short note on H. orientalis subsp. guttatus by Mathew in The New Plantsman, 1994. vol. I, part 3.

Rekha Morris - Pendleton, South Carolina

In response to Norman Deno’s query about where good color forms of Helleborus orientalis hybrids can be obtained, I would like to recommend the selections of British hellebore breeder Graham Birkin. Birkin breeds for color and has only recently offered divisions of his hybrid hellebores via mail-order for American gardeners. His new Web catalog can be found at http://www.hellebores.hort.net.

Birkin’s catalog is an image catalog, so it may be slow to load for those with slow modems, but it’s worth the wait to see all those gorgeous flowers! He offers doubles and anemone-flowered forms as well as “blacks” and blues, pink and red ranges, yellows, apricots, and whites.

Orders can now be placed for delivery this spring or fall. A selection of his hybrids is also available at the following American nurseries:

Russell Graham—Purveyor of Plants, 4030 Eagle Crest Road, N.W., Salem, OR 97304. (503) 362-1135. Catalog $2. E-mail: grahams@open.org 

Plant Delights Nursery, 9241 Sauls Road, Raleigh, NC 27603. (919) 772-4794. Catalog 10 stamps or a box of chocolates. Owner Tony Avent lists some of the dark forms under ‘Birkin’s Blacks’ in his online catalog. http://www.plantdel.com 

Marge Talt - Potomac, Maryland

My experience with H. niger contrasts with that of Brian Mathew in his book, Hellebores. He noted that the Christmas rose rarely blooms as early as Christmas and went on to say that “it is not the easiest plant to grow and one seldom sees good plants in gardens.” In this region at least, given conditions to its liking, the common form of H. niger will, in time, form luxuriant clumps elegant in flower and foliage—and yes, I do have one clone that truly deserves the designation “Christmas Rose.”

This selection was obtained in 1978 from Wayside Gardens, which was then located in Mentor, Ohio. This plant has bloomed as early as Thanksgiving—which may explain Deno’s fall sighting—but it tends to flower with near clockwork precision between December 1 and December 10 and is at or near its peak for Christmas.

A much smaller plant than my younger, later-blooming clones, it normally produces 12 to 20 flowers a year. These are unusually large, to four and a half inches in diameter, compared to four inches for the later-flowering types. Its leaf segments are also distinctive in that they are only half as wide, much less strongly toothed, and lack the occasional deep embayments of the later flowering forms. These distinctive features suggest this particular early-flowering selection may represent a separate genetic strain.

Over the past 21 years, the early flowering clone has produced only a single seedling. If typical, this lack of sexual and vegetative vigor may help explain the scarcity of this selection in cultivation.

George Phair - Potomac, Maryland

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