Repairing Snapped Branches

A favourite bonsai is blown off a bench during strong winds and several important branches get broken. Or, when wiring a tree, a branch is bent a little too far and the branch snaps.

Judging by the number of questions raised on the bonsai forums over the years, these are events that have happened to all of us at least once. Very often an enthusiast has tried to repair the branch themselves and though the cambium layer repairs itself, the wound keeps reopening and is a weak point in the branch.

So how do you successfully repair a snapped branch? Or does it just need to be removed and regrown? Though I have seen many repairs and remedies offered by fellow enthusiasts (ranging from the ridiculous to the sublime) the best way of repairing a snapped branch is extraordinarily simple. I've snapped this thin Privet branch and it shows a pretty typical scenario. As a two-year old shoot, the wood is quite brittle so it has snapped on one side while being bent into position.

If the branch is completely separated into two pieces, it cannot be repaired and should be pruned away and the wound cleaned up. However, if one side of the cambium layer (branch) is still attached naturally, it can literally be glued back together. A spot of superglue (any brand) is put onto the surface of the wood...... 

................ and the branch is glued back together. It really is as simple as that!

The superglue glues the woody parts of the branch together very tightly and supports the branch while the wound (and cambium layer) heals. Eventually both sides of the snapped branch grow together; this can take as little as 3 or 4 weeks on vigorous branches during the growing season.

I find that the repair is so strong that the branch can be manipulated (wired into position) within 5 minutes of the repair being made. The repair site will have lost its elasticity though, so don't not try to create a bend at that point.

Any excess superglue will dry a white colour on the surrounding bark. It is unsightly so try to avoid using too much superglue when making your repair but any excess will fall away naturally after a few months.

Finally, always keep some superglue to hand. If you do a lot of wiring you will find it becomes a valuable tool!

Additional notes:

• I find that as thicker branches are stronger and more robust they tend to splinter rather than snap and so this article focuses on branches up to around 1/2" thick. However, repairs can be made using this technique with thicker branches.
• Superglue is not poisonous to a tree and will not harm the tree or the branch, nor will spilt superglue damage any leaves (it just looks awful).
• Superglue can be used on woody or tender shoots.
• There is no need to wrap or protect the glued area on branches of less than 1/2", above this diameter, a thin spread of vaseline over the damaged bark/cambium is more than sufficient.
• There is no need to wire the branch or for the branch to be wired for the repair to be successful
• Though superglue is not necessarily the strongest glue on the market, it is the fact that it dries very rapidly and will tolerate moisture (in the wood) that makes it so effective for repairing branches.
• This technique can be used on all tree species; coniferous, deciduous or broadleaf tree during active growth or during dormancy.
  
  

(Article written and kindly provided by Harry Harrington. )