I put a bamboo fence up a few months ago and carefully hand picked poles that had no splits or cracks. Then I cut and painted each pole, top to bottom and inside and out with two coats of oil based spar urethane by Varithane. It added a very slight yellow-brown tint that looks completely natural. This took a while but so far everything seems to be holding up. If you can help it, make sure the bamboo does not touch the ground. All posts and ground supports should be pressure treated wood. In addition, I cut the top of all vertical poles near a node so they wonÂt fill with water.

If you are going to use black twine, I was told that should be coated as well.

A Japanese Landscape Designer/Installer I've been working with (off and on) for many years always coats the bamboo and twine with varnish, but to tell you the truth, after a year or two the varnish starts to yellow and chip off, and just looks awful. So, unless you're going to lightly sand and re-coat every other year I'd suggest just leaving it alone.

There is a difference between true varnish and oil based poly-urethane. The latter is designed for use outdoors and should last longer, but I couldnÂt say how much longer. The weather here in Los Angeles is much like San Diego and quite temperate (nothing like Croatia). For me it's too late, so I guess IÂll know in a year or two how it holds up.