Wednesday 7 November 2012

Espalier - Site Prep Part 2 - Bamboo

A sketch of a Belgian Fence Espalier

If you have been following along, this post picks up where the last post left off. With wire in place, the next step of getting things ready for the trees was to build a growing frame of bamboo. I have enough trees to plant across the backyard on 3 foot centres. I know that is tight, but using dwarf rootstock, and training the trees results in smaller root structures. Besides, the Internet says it will work. Who am I to question the Internet. Based on my 3 foot centres, I needed to set up bamboo with a pole every 3 feet. Since I wanted to make a "Belgian Fence" pattern (image below) I needed to set the bamboo on a diagonal, in both directions to get the fence going.

 First Attempt

My first try was in the dark, right after I got the wires set. I was tired and cold, and I thought it looked pretty good. I stopped until morning when I figured I could carry on with the bamboo. I was lucky I did.
 There is nothing wrong with the pattern or geometry, but if I had continued with the bamboo set like this, I would have ended up with stems coming up 3 feet off the ground before beginning to be formed in to the weave to make the pattern. With only 2 crosses per plant, the fence would be weak, and the ground clearance would be much higher than I was aiming for. I took down 2 of the poles and set out for a second attempt.

In order to fasten the bamboo to the wires, I am using plastic zip ties. They are flexible enough to allow some adjustment after placement, but strong enough to hold everything in place. Once the whole setup is in place, I may lash together the bamboo crosses with some jute twine, and cover the zip ties with more of the same.

Second Time's the Charm

In order to bring things closer to the ground, I re-set 2 parallel stakes, shifting them sideways until my lowest crossing was just above the lowest wire. The first pic below is before re-setting. Further down in this post you can see the difference once I reset things....

The lowest X's are now about 20" above grade. This made the weave tighter, and stronger. It also meant the tips would cross just below the top of the fence. Having that extra cross in each pole made a big difference. See third pic below...

Keeping things lined up

I keep telling myself that this project isn't rocket science, and doesn't require absolute precision. Working with bamboo, or any natural material means there will be some variation from piece to piece, and within the pieces themselves. But still, it is important to keep things square and level. To that end my most important tools on this portion of the job are a roofing square, tape measure, and pliers.

The roofing square allows me to check that each stake is set at 45° to the wires. This keeps each piece of bamboo parallel (or mostly parallel) to the next one.  What I have been doing is setting the zip ties on the bamboo loosely, getting the spacing about right with my tape, and then tightening. Once tight, I use the square to check that the stake is at 45° and then whack it into square with whatever is handy. Once it is square and properly spaced, I use the pliers to tension the zip tie as much as possible.

As a final check, I place the 90° corner of the square at the X formed by the poles and verify that they are square to each other. A couple more whacks and things are usually set.

Bear in mind that perfect is the enemy of good, and as the fence that this is anchored to moves, as the trees grow, as the wire looses tension, as the bamboo weathers, the whole frame will move. 

Pattern Making

With the first five pieces of bamboo in place, the pattern begins to present itself... It takes about 15 minutes per pole to set the bamboo. Thanks to daylight savings time setting in, I only have about 1-1/2 to 2 hours per night to work on this. I managed to sneak out for long enough to set another three poles after breakfast this morning.
And by the time I left for work, this is what the fence looked like. I only have another 9 poles in my bundle of 25. I'm not sure if that will be enough or not. Maybe my math is off on all this. (13 trees, 2 poles per tree = 26 poles??)



Not too shabby looking for a first attempt at this sort of thing, and no major screw ups yet. With any luck I can get out there for another half hour at lunch, and again tonight and get some more set. Maybe I'll even get SWMBO or Chuck out there planting trees tonight!

Meet the trees here, or skip ahead to planting day here.

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