By Thomas J.

Last month I discussed mainly shaping and styling the chinese elm. This month I will end the article by discussing the difference between the chinese elm and the zelkova serratta, a tree whose name is often placed on the chinese elm because their appearance is quite similar yet very distinguishable. I will also touch briefly on a few of the health hazards of the chinese elm; that being the problem of Scale, and Black Leaf Spot.

Once a bonsai enthusiast has seen for himself in person a zelkova serratta and a chinese elm, the differences will be quite apparent. The main difference being the size and shape of the leaf of the zelkova as compared to that of the chinese elm. In this picture the leaf on the left is that of a zelkova, and on the right a chinese elm. Notice the size of the zelkova as compared to the chinese elm. Also notice the sharp edges and tip of the zelkova, while the chinese elm has more of a rounded tip and softer edges.

While younger zelkovas and chinese elms have bark that are pretty similar, as the chinese elm gets older so does its bark in appearance, while the zelkova stays pretty much the same. The picture on the left is that of a zelkova about twenty years old, while the picture on the right is that of a chinese elm about the same age.

One of the biggest problems with chinese elms is their tendency to get Black Leaf Spot, an awful fungual disease that will do serious harm to your tree if it's not treated ASAP. This disease starts its life in the Spring when the new leaves have started opening and the Spring rains are quite often. It only affects new tender growth that hasn't hardened off yet. After the leaf has been infected it will follow through to the branches making them look like they've been burnt at the tips and cause them to shrivel up. The tree naturally is under significant stress because of this. If steps aren't taken to completely eliminate the fungus, the tree will probably die. Even after treatment begins the damage will probably last throughout the rest of the growing season. A serious treatment with an antifungual must be started immediately, and a watchful eye to see that the disease is being eliminated during the course of the treatment. A product called Daconil is a good one to use for this. Use it by drenching the crown of the tree and work your way down so as to wet all leaves; those that are infected and those that are not. Do this with your watering can.

All this trouble can be eliminated though in most cases, by not doing one specific thing, and that is to not water the new leaves until they harden off. This will probably around six to eight weeks form the time they open. Once you notice the color of the leaves turning from light green to to bit of a darker green, and they don't have that tender look to them, you should be safe. And when I say no water on the leaves, I mean no rain water also. That means if you know that rain is in the forecast, you must do whatever you have to to shelter it. Sounds pretty drastic I know, but this simple precaution will eliminate a lot of trouble later on. If your tree should come down with this disease, continue to fertilize as usual even during treatment to allow the tree to bear the stress that it will be going through. As I said the damage will remain throughout the growing season, but next Spring should have the tree showing no signs of what it went through the preceding year.

The other problem that chinese elms are prone to, at least in my neck of the woods, is Scale. Many people have said that Scale only attacks trees that are not healthy, and because of this their resistance is low allowing the Scale a foothold. Sounds reasonable, but I have quite a few chinese elms and all are in optimal health, yet the same trees will be prone to Scale no matter what. In other words, no matter what I do, those that will get it will, and those that don't, won't. At least I know which trees to keep an eye on, and to treat them when necessary. For me there are two kinds of Scale that are attracted to my chinese elms, and these are the ones that I will touch on in this article. The first one will be the hardest to detect, since it is almost microscopic in nature. This is what it looks like from a normal viewing position. From this normal viewing position, it will be much easier to see when the area where the infestation is located, is wet. The dark wet area causes the white Scale to stand out really well.

And this is what it looks like closeup.

You would think that something so small couldn't be that harmful, but believe me it is. I first encountered this type of Scale when I started noticing some of my branches drying up. I was somewhat new to bonsai and couldn't understand why my trees looked like they were drying up when I knew I was watering them right. I took a branch that appeared to have some small white stuff on it, and was one that was drying up, to a fellow club member. He informed me the branch was full of Scale, and they were sucking the branch dry. He advised a treatment of Horticultural Oil, and to try and scrape or brush off as much as I could. Now this is easy on large branches or a portion of the trunk, but impossible on thin branches. Again, prevention is the best medicine for this. I now use a dormant oil at least once during the winter dormancy, and I keep an eye on those trees that always get it, and nip it in the bud before it goes rampant. One other thing I've noticed with this form of scale, is that it is more prevalent during very rainy conditions that at any other time.

The other type of Scale is a lot easier to see as you can tell in this photo.

Something like this would be easy to just scrape of with your finger or some other object. If you have a rather large tree though and it is pretty much infested with these critters, it would be much easier to just use this simple solution which works really well, and could probably be used on both types of Scale.

Pour a solution of 1 to 2 tablespoon dishwashing detergent, 1 tablespoon of vegetable oil into a plastic gallon and slowly add water to fill the gallon jug. fill this solution from the gallon bottle into a spray bottle and just before using , add 1 to 2 two caps full (from the rubbing alcohol bottle) of rubbing alcohol and spray immediately. If you do not use the full bottle of spray, I suggest the next time you are going to use the soap/alcohol solution add the same amount of rubbing alcohol again, since the alcohol will evaporate. Spray on plants covering all leaf and stem surfaces. You may have to spray from three to four times with intervals of three days.

Well I hope this article was somewhat helpful to those that are bonsai beginners in general, and to those who maybe have never had a chinese elm in their collection but are maybe considering adding one now that they know a bit more about them.

Note: There are those who believe it is alright to grow the Chinese Elm indoors, and there are those who say otherwise. It is my personal belief

that these trees are mainly outside trees. Though many have had good luck with them indoors, it is actually taking them out of their natural environment. For those concerned with the extreme cold of winter, an unheated garage will keep the tree in its intended dormancy while out of the drying winds and freezing temps of the winter months.

END OF PART TWO