If you post the question, “Should I seal the wounds on my tree after I prune?” or, “What wound sealer do you use?”, you will get many different opinions. Anything from, “I don’t use any at all, it is not needed.”, to, “I seal everything.” What should an aspiring bonsai artist do? Is there a middle ground? I personally think that sealing wounds is a good idea and helps them heal quicker. I don’t seal everything, unless it is and azalea, just larger wounds on a trunk or the ends of pruned branches that are larger than 1/8 inch.
I usually only use the expensive stuff on azaleas, and for the rest I make my own. It is very simple and very cost effective. I use exterior latex caulk. You can get it at any home improvement store and even Walmart for only a couple of bucks. It is also comes in many colors so you can match the bark of your tree or even blend to get a custom color. It is a little thick right out of the tube (I have used it this way, though) so I squirt some in a small jar and thin it with a little water. After that, just use a craft stick or some scrap wire to apply it.
The putty type would sealant is just as expensive and you have the same problem with availability. I have used it in the past and it is good stuff. On day as I was applying some I remembered a product that I used years ago when working as an electrician, you know, one of those “light bulb” moments. We often used a material called “duct seal” to add additional protection from moisture. It is a grey putty-like material that has the same consistency as the putty made for bonsai. You can get one pound of the stuff for about three bucks at Home Depot or Lowe’s, it can be found in the electrical department. That is at least three times as much as you get in the little tub of bonsai putty. I have been using it for a while now and I can say that it does everything the expensive stuff does.
Another sealer type product that I use that is available at the hardware store is epoxy putty.
It is useful in the repair of trunks and branches. I have several large trees that have large wounds that had rotted some before they healed. You can clean out the rot and fill the void with the epoxy putty. Be sure to smooth out the putty even with the wood. The callous will cover over the epoxy just like exposed wood. I have done this on Japanese maples, American Hornbeam, and ficus so far and all have healed over the epoxy easily.
After the epoxy cures, just trim the edge of the wound to stimulate the callous to start forming. Then seal with the putty.
As you can see, there are a few products that are easily had that can be used for sealing wounds on bonsai. Pick some up and give them a try, you might be surprised and save a few bucks, that will free up more money for beer.
As you can see, there are a few products that are easily had that can be used for sealing wounds on bonsai. Pick some up and give them a try, you might be surprised and save a few bucks, that will free up more money for beer.