The Japanese Landscape Architect I work with occasionally uses varnish on his bamboowork, and on the black tie material, but this really doesn't protect it for more than 1 year, unless it's re-applied.

You know, they do have fake bamboo now (looks pretty good) and also synthetic black tie material, that both last a long time. Sorry, haven't bought and used any myself.

No matter how much one appreciates the weathered, subtle look of aged materials and the evidence of passing time, it is discouraging to see a fence degrade so quickly. I have used braided black polypropylene rope to replace the palm rope. It lasts a long time but isn't much fun to work with and looks shiny when new. Spraying bamboo with varnish does help, I have also used something called "silicone conformal coating", available in electronics stores (like Frye's on the west coast). It is meant to protect electronic circuits from moisture, and works pretty well (better than varnish or lacquer), but you still need to reapply about yearly for best results. I also found that it isn't the cold as much as the moisture that ages the bamboo. Maybe if bamboo doesn't grow in the local climate, we should use hardier materials. I have seen plenty of plastic bamboo, even in Japan, but you don't want to get within 20 feet of it if you want to preserve the illusion.

It is extremely important that bamboo be properly cured for decent longevity. Even then, bamboo fences usually need major repairs every 5 to 7 years, depending on climate and exposure. I was taught to use copper wire for structural ties, then cover that over with the black palm rope. Hida Tool company was able to get heavier grades of palm rope on request. You might try spraying the finished knots with fixative, just don't tell anyone!

As part of the Intensive Seminar on Japanese Gardening at the Kyoto Univ. of Art and Design, we attended the workshop of a 10th generation bamboo dealer in Kyoto.

From him we learned many fascinating facts, including (as DonPylant says) that how the bamboo is cured is critical to its longevity and good appearance. He explained and demonstated various methods of curing. The better the bamboo, the more expensive.

A little sampling of other interesting facts:

Every piece of bamboo has 57 nodes per stem. These are all in evidence in a bamboo shoot if you cut it in half. When the bamboo "grows" (at a rate of up to 1 meter 25 cm per day) the internodal region simply expands...

Kyoto is the perfect place to grow bamboo, and some groves there have been cultivated for 1200 years.

A bamboo forest is a good place to be in an earthquake because the mat formed by the rhizomes will keep you from falling into a fissure if one opens up under you.

Lee

Lee, you are so fortunate. May I ask, was your bamboo dealer named Oto-san? Was the instruction linked to Kiyoshi Yasui?

Hi Don ---

Yes, I feel very lucky to have attended the intensive seminar and to visit all the places they took us.

No, the bamboo dealer was named Nakagawa. We were happy to see that his son (generation #11) was also working in the shop. Mr. Nakagawa was 63 years old and had been working in the shop since age 18 (missing only the years during which he attended university).

More bamboo trivia (from Mr. Nakagawa):

Thomas Edison tried over 100 varieties of bamboo for the filament in his first electric bulb, and the only one that worked was Kyoto bamboo.

and...

700 species of sasa (groundcover bamboo) grow in Japan.

If anyone is interested, I'll post the whole procedure Mr. Nakagawa uses for curing bamboo so that it will last for 10 years outdoors. (Of course this procedure starts with fresh Kyoto bamboo, so you might not get such good results from bamboo of lesser quality...).

Lee

Lee, I would be interested in Nakagawa-san's procedure. Please post - might even be a separate subject?

Did you visit the Bamboo museum in Kyoto? It has an Edison bamboo filiment bulb.

This is the procedure I wrote in my notes. My apologies if anything is wrong. Please correct if anyone has other information. These instructions apply to Kyoto bamboo, and this is the expensive, time-consuming method which produces long-lasting bamboo (lasts 10 years outdoors).

1. Cut bamboo in Nov. or Dec.
2. Dry upside-down for one month.
3. Light a gas brazier. The one they used was about 24" long and produced a glowing orange heat.
4. Hold the bamboo stationary over the brazier for about 60 seconds so that one section heats up.
5. Turn the heated part upwards (and take it off the brazier, I believe) and rub the heated part vigorously with a soft cloth. It becomes smooth and shiny.
6. Reheat and re-rub the same spot again. (It is possible this should be repeated more than twice).
7. Repeat this process for the whole piece of bamboo.

Mr. Nakagawa said that using this method, two workers can prepare fifty 2-meter-long sections of bamboo in one day. The piece they used to demonstrate the technique to us was about 5" in diameter.

Lee

Any experience using shellac to try and extend the life of bamboo structures exposed to the weather? A co-worker tells me that an annual dilute coat was the practice of her family in rural Philippines. I don't know if shellac is superior to other products or just what they had. Also I get the impression that function of structures was more important than looks. Shellac's appeal is that it could be applied with relatively inexpensive spray equipment and is a natural product.

Shellac helps. I have a treated sodegake that has withstood weather for 5 or 6 years now. An annual re-shellacing probably will extend the life of the bamboo for years. Don't forget to protect the bamboo from ground contact, though - prolongued contact with moisture from soil will rot bamboo even with protective coating.

Some of the best bamboos for construction are Hachiku (Phyllostachys nigra 'Henon') and Madake (Phyllostachys bambusoides). These species have thick walled culms and have proven to be some of the most durable bamboos for construction.

Harvesting should be done in the winter when moisture levels within the culms are at their lowest. Spring is the absolute worst time to cut bamboo for crafts as water will actually be standing within the culm cavities. Culms which are 4-7 years old will be the strongest since they will have a high silica content. Locate these by looking at the ramification of the branches or by the color or dirtiness of the the culm.

Cut the culms, strip the branches and clean the culms. Place in a sunny spot for about 2 weeks until they lose their green color, and then move them to a dry, shady location to cure for 3-6 months.

-christian m.

Christian, do you have local sources for this bamboo?

Godsdog and Cady, the designer of our local garden would not give permision for preservative treatment until recently (a new generation at the company). I don't know if this is due to a new understanding of climate/culture needs or based on new fiscal strangulations : (

Hello Don,

Yes, I know of two groves of Hachiku growing here in Greenville, SC, and i have permission from the property owner to harvest from one of them. Harvesting the bamboo is hard work, but it results in high quality material. It took me about 4-5 hours to select and cut enough bamboo for 24 ft of Yotsume gaki. I am not aware of any wholsale source for these bamboos.

-christian m.

Here is a link that might be useful: Yotsume gaki

Thanks, Christian. The city of Kumamoto has agreed to send us the material we need. Thanks for the lead!