Message for Rhodyman

mainegrower(Z5b ME)May 30, 2010

I saw news of your nursery visits in one of your replies to another question. How about writing an account of the new and exciting varieties you saw in your travels for all of us rhododendron addicts? Hachmann's nursery in Germany, especially, seems to be developing great new hybrids, but there are no doubt others.

I wonder if you could also give your personal assessment of how rhodendron nurseries in general are doing. It seems as if a large number, both retail and wholesale, have closed their doors in the last few years. How much danger are we in of having only the dreary, same big box store varieties and nothing else?

Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

I am not an expert on the nursery industry. My interest was mainly to photograph the flowers of as many varieties as I could find. I saw lots of varieties that I had never even heard of. One thing that surprised me was the large number of old "iron-clads" that they were raising such as Nova Zembla, Roseum Pink, Roseum Elegans, English Roseum and Lee's Dark Purple. These are old fairly fool-proof plants. But they also raise many yellow rhododendrons and exciting newer hybrids.

Germany, and most of Europe in general, raises most of their rhododendrons on grafted plants. Many of their plants, if grown on cuttings on their own roots, as would be done in the US where grafting of rhododendrons is virtually unheard of, would be 1) too difficult to root to be commercially successful, 2) too tall and leggy, and/or 3) too difficult to raise due to low pH demands, susceptibility to root-born diseases, or poor root structures.

One thing that I found interesting in Germany was that there are basically two different methods of raising grafted plants. One method, the more conventional method, has something like Cunningham's White or Inkarho patented rootstocks that are rooted from cuttings and grown for 2 years. Then the scion is grafted on to the root stock using a side graft. The graft is wrapped with a rubber band type material until the graft takes.

The second and newer method takes cuttings of both the scion and the root stock and grafts them together and roots them at the same time. For about 1.5 to 2 inches each cutting is cut from one side to the center of the base. Then the cut areas of each cutting are mated with green tissue touching green tissue. Then the two cut areas of mated cuttings are wrapped with raw cotton string and dipped in a powdered rooting hormone and stuck in a rooting soil-mix. The raw cotton string will eventually rot in the soil.

The main rhododendron growing region of Germany is in northwest Germany which was once a large peat bog. It was a swamp. Success by the Dutch in reclaiming such land caused the Germans to build a ditch and canal network with windmill powered pumps to drain the swamp. Then the peat bogs turned into ideal areas for growing acid-soil loving plants such as rhododendrons and azaleas. During this process the peat bogs died. The sphagnum moss could no longer grow without the swamp. In some areas peat was harvested. In other areas plants were grown in the peat.

There are more rhododendrons produced here than in the rest of the world combined and the scale is staggering. These family-owned firms are usually 2-3 generations old and are able to pass down the family tradition. They use gantry irrigation, water recycling, computer controlled potting and grading and greenhouses whose rooves lift as the temperatures rise. Most of the garden work is done by Polish laborers and some work such as grafting is sent to be done in Poland.

Today things are done much differently. First, most plants are grown in containers with little or no peat moss. They tend to use more bark dust and less peat. It gives them a much better yield. They are not raising the plants in the peat bog, but in containers placed on water proof fabric on top of the peat bog. The growing areas are sloped in such a manner that they can collect all irrigation and rain water that is not used and drain it into ponds that are used for irrigation. In a normal season they can get by almost entirely on rain water.

The buying habits of both Germans and Americans are shaping the nursery industry. People tend to buy from large box garden centers and home stores rather than the local nurseryman. There are now two very successful types of nurseries, 1) the mega nurseries that supply most of the garden centers and home stores and 2) the specialized nurseries that supply landscape architects with large expensive plants. Some of the nurseries in Germany did both.

I will try to put together a plant list in a future posting.

The blog in the link below is written by author, plantsman and plant explorer Ken Cox of Glendoick, Scotland, and does an excellent job of describing our trip. He neglected to mention that we had a couple that run a large nursery in Brazil and are introducing rhododendrons to Brazil.

Here is a link that might be useful: International Rhododendron Conference in Germany

    Bookmark   May 30, 2010 at 7:31AM
Thank you for reporting this comment. Undo
mainegrower(Z5b ME)

Thank you for the information as well as the link - I really enjoy Kenneth Cox's blunt honesty as a contrast to the more usual bland diplomacy in garden writing. I look forward to a plant list in the future.

The second, "double" grafting method is interesting, but I'm not at all sure how it works or what the advantages might be. Your description seems to indicate that both the scion and rootstock are producing roots. If the main purpose of grafting is a more adaptable, heat and phytophthora resistant plant, why would you also want or need roots from the scion?

Thanks again and please continue with more information when you can.

    Bookmark   May 31, 2010 at 5:39AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

You have a good point. They probably are sacrificing some of the advantages of grafting. But if the phytophthora only infected the scions root's, the root stock's roots would still be functional. In any case at least one very major grower finds it speed up his production by 2 years. Another way of looking at it, he doesn't have to have nursery space for rooting Cunningham's White and Inkarho cuttings for 2 years which is what some of his competition is doing and he used to do.

Â
Here is a photo of a cutting graft, the new simultaneous graft and rooting, after it rooted and grafted together and the Cunningham White cutting was trimmed back leaving the "scion" at Schröder's.

Â
Â
Here is a photo of a conventional splice graft of a scion onto a rooted rootstock at Hachmann's.

Â
Â
Here is a photo of conventional side grafts of a scion onto a rooted rootstock at Hachmann's.

    Bookmark   May 31, 2010 at 8:42AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

Here are the recent introductions we saw at Hachmann's. The photos are from Hachmann's website:

Attraktion


Candy Striped Pink


Christian Gehler


Denise


Duftwolke


Fresiane


Gunter Dinger


Hans Hachmann (Night & Day)


Karl Naue


Konfettiregen


Maroon Sappho


Matador


Metallica


Midnight Beauty


Minas Snow


Papaya Punch


Orakel


RhododendronPark Graal-Müritz


Raphaela


Rudolph Heinemann


Sariska


Saskia


Silver Jubilee


Tanaga


Veronika


Yak "Blue Leaves"


Yak "Cup Cake"


Yak "Mariola"

    Bookmark   May 31, 2010 at 10:06AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

Here are the recent introductions we saw at Schröder's. The photos are from their catalog.


Erika Guyens


Guyens's Fasching


Guyens's Peking


Picotee


Yak 'Dear Barbara'


Yak 'Herbstzauber'

    Bookmark   June 1, 2010 at 12:20AM
Thank you for reporting this comment. Undo
mainegrower(Z5b ME)

Thank you for posting the photos - some of the Hachmann hybrids are just spectacular. (Interesting also to see Minas Snow from Nova Scotia and Papya Punch from the PNW included.)

Your explanation for the double grafting technique makes a lot of sense. The scale of annual production in Germany is really mind boggling, so any savings in time and space would be worthwhile. (As long as you have a source of skilled and probably not terribly expensive labor from Poland).And as long as the existence of phytophthora susceptible roots intermingling with resistant ones doesn't lower the overall disease resistance.

In his book, Kenneth Cox argues that grafting could make many more varieties suitable for the eastern US by eliminating the phytophora problem and related lack of heat resistance. 'Capistrano' is a case in point. I know it is very difficult to grow in much of the East. Here in Maine - at least so far (has only been widely available for about 5 years) - it's proving to be an excellent variety. Cooler temperatures, especially at night, is the most likely explanation. Capistrano and any number of other heat sensitive varieties grafted on Cunningham's White or Caroline ought to be growable in many more areas.

    Bookmark   June 1, 2010 at 5:33AM
Thank you for reporting this comment. Undo
ego45(6bCT)

Rhodyman, thank you very much for sharing such usefull info. Wish you all the best.

    Bookmark   June 1, 2010 at 9:48PM
Sign Up to comment
More Discussions
Azalea ID
This is an azalea left over from some that my great...
alabamatreehugger
Blanchie
My Rhododendron leaves are green, but have started...
blanchie7
what to do to thicken native azalea canopy
My Florida Flame is lovely in bloom, healthy, with...
vossner
Is this a rhododendron?
Moved here in July. Still trying to figure this out....
ssmo
Anybody out there have luck with Rhodos in Southern Arkansas?
Looking for any feedback from Houzz readers who have...
Rusty Empire
Sponsored Products
Chalkboard Sign
$8.99 | zulily
'Peanut Butter' Wall Sign
$9.99 | zulily
'The Things You Are Passionate About' Wall D̩cor
$24.99 | zulily
'Mom You Mean So Much to Me' Glass Plaque
$14.99 | zulily
'Beautiful Things' Memo Board & Magnets
$14.99 | zulily
Sofia the First Personalized Peel & Stick Decal
$19.99 | zulily
Personalized Filigree Rectangular Mat
Signature Hardware
Medium Blue USA Map Aqua Shield Doormat
$24.99 | zulily
© 2015 Houzz Inc. Houzz® The new way to design your home™