You have been engaged in the wide world of bonsai for a while and you want to upgrade your collection with a really nice tree. You spot a tree for sale at a show which makes your dreams come true. Talking with the owner of the tree you find that the tree was originally purchased from a nursery in a gallon can twenty years ago. The price for the tree will probably be in the range of a few hundred to a few thousand dollars. So why is the tree so expensive? There are at least three reasons which figure in pricing a tree.
The most obvious reason is the appearance of the tree which is what attracted your attention to the tree in the first place. All the branches are in the right place and the tree is showing all the signs of great age such as a thick trunk and aged bark. The cost of the tree is in part due to the skill that was needed to bring the tree to the current stage of perfection Bonsai trees are living trees and as a result are constantly changing. After twenty year of careful attention the tree is not considered finished but only a little is needed to maintain it as a fine bonsai.
The second factor in pricing a tree is the simple law of supply and demand. There are fewer fine bonsai trees on the market than there are people that want to buy them and this drives up the price.
There is a third and less obvious factor in pricing a bonsai and that is the fact that the owner has asked a simple question each day without fail: does this tree need watering? Over the twenty years he has owned the tree, he has asked this question without fail for an amazing 7,300 days. If it is pouring rain in the middle of winter the answer to the question is easy but non the less the question is asked. The pricing of the bonsai also reflects this remarkable and unfailing devotion to the tree over the years.
Watering your bonsai is a lot like feeding the family dog. It is not hard to do but must be addressed every day. If you skip feeding the dog for a week, the dog will be pretty mad at you and if you skip feeding him for a couple of weeks you will find that the dog has packed up and left. It is the same way with bonsai. Skipping water for a week will make your tree look pretty sick and if the drought extended to a couple of weeks your tree will be in need of a decent burial because it will no longer be in the land of the living. You might ask why all the fuss about constant watering? After all, trees in nature are not watered every day. The answer to this question is lies in how roots function. When the roots become completely dry, they die. If the soil that the tree is planted in does not drain well, the roots can rot. To prevent this from happening, soils can be chosen for our trees that drain well. These soils can also dry out very quickly leading to death of the roots. Not a good thing. Thus water becomes a major issue to maintain healthy roots We select soils that allow for good root growth and are compromises between these two extremes. Our trees look best when potted in shallow pots and the shallow pots aggravate how fast the potting medium can dry out. In fact, in warm weather the soil in a bonsai pot can completely dry out to the bottom on the pot as quickly as a couple of days and this leads to dry (and dead) roots. There are summer rains in the natural habitats where most of the trees that we select for bonsai grow. The soil near the surface may dry out between rains but there is enough moisture beneath the surface to prevent the loss of roots. The soil does not dry out completely as it would in a shallow pot.
What happens in places where there is little or no summer rain? Native California oaks are found in such places. If we neglect to water our oak bonsai for more than a few days, they will die. Why the difference? In the wild the oaks get by with the lack of summer rain in part by going semi dormant in the summer. Probably part of the dormancy cycle includes the roots slowly hardening off to prepare for the dryer soil. Also, although the soil appears to be dry at the surface, the level of moisture left deep in the soil is enough to sustain the dormant roots. The roots of the tree grow deeply to find the residual moisture. If the winter rainfall is poor, the tree will suffer because of low residual moisture content of the deep soil and the tree may not survive an extended period of drought lasting several years. One can speculate that in nature the soil near the surface slowly dries out as summer approaches, leaving the roots time to prepare for a period of low moisture. Oak bonsai however can dry out quickly in the fast draining soil leaving no time for the roots to harden off, so they die.
How often should you water your bonsai? That depends on the soil you use and how quickly it dries out as well as the weather where you live. Obviously on hot days the soil will dry out more quickly. Is your tree in full sun or part shade? This, too, influences the dry out rate. Taking all these factors into account you should probably water about every three days or less in cold weather, every two days in mild weather and every day in hot weather. There are only rough guidelines and, of course, actual water needs for your trees may vary depending on your specific circumstances. The crucial thing is to ask every day without fail the question does this tree need water?