By Tivon Feeley
Forester
Iowa State University Extension
The art of bonsai is one of the oldest plant dwarfing techniques used. The practice of bonsai is attributed to the 14th century Chinese, who transplanted naturally dwarfed trees from the wild into containers.
The most prized plants grew in high altitudes on very poor soils with a contorted growth pattern formed by the harsh conditions. Human appreciation for bonsai plants has grown over the years earning them a prestigious spots in gardens and homes.
The word bonsai is a Japanese word that literally means “tray gardening.” The concept is simple: restrict the growth of the plant’s roots and shoots, while allowing the trunk to grow. The end result is a dwarfed plant that needs occasional pruning and shaping to maintain its size and appearance.
Most bonsai trees can take years to develop depending on the tree selected. Currently, there are many bonsai trees that are more than 100 years old. The most commonly used trees are red maple, Japanese maple, elm (Chinese and Siberian), birch, mulberry, pine and junipers.
To start a bonsai tree, purchase a seedling or rooted cutting and plant it in a shallow 4 inch container. Line the container with a layer of very small rock. Next, selectively root prune the tree with by-pass hand pruners to fit into the container. After the tree is situated, fill the container with a well-drained potting soil and water the plant well. After planting, place the bonsai tree in sunny location.
Bonsai trees tend to dry out rapidly due to the relatively small amount of soil and remaining root system. The plants need to be monitored on a daily basis to make sure that the soil has not completely dried out. When the soil feels dry to the touch, irrigate the tree thoroughly. Placing the planting container on a tray that can hold the excess water will help reduce the watering frequency. Be careful not to over water the plant to the point where it sits in the water on the tray for over one day. Fertilize with a diluted balanced fertilizer (10-10-10) once a month to maintain the plant health.
There are many styles of bonsai.The simplest is to allow the trunk to grow straight and prune the tree periodically to maintain a symmetrical form. A more challenging method is to braid two branches together and manipulate where they grow using copper wire to guide them. To accomplish this, loosely wrap the end of the wire around the branches, position the branches at the angle desired, and gently wrap the wire around the trunk to hold it in place. Over time the branches will maintain that growth pattern and the wire can be removed.
After planting care is fairly simple. Prune or pinch back any errant branches to keep the plant in its desired form and remove any dead or dying leaves. If the bonsai tree starts to wilt, even with proper watering, simply remove a few healthy leaves to reduce the demand on the roots for water and nutrients.
Bonsai trees generally require repotting to the next size container every two or three years. Repotting in too large of a container will result in rapid growth, making it difficult to maintain the trees form. Early spring is the best time to repot indoor and outdoor bonsai trees in Iowa.
Bonsai trees make a great family winter project. Check out books at your local library for more tips and ideas on growing and shaping bonsai trees. Many of the prime bonsai tree species (maple, elm and mulberry) can be found growing in your own backyard and along fence lines. Please check out this Iowa State University Extension website www.extension.iastate.edu/pages/tree/ to help you identify these common tree species.
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