Can you container grow this tree and prune it to keep it small for wintering inside in a zone 4 area?

Answer #1 · Maple Tree's Answer · Hi Kristi-The Purple Ghost Japanese maple is a medium size Japanese maple, 8 to 12 feet in height, and can easily be grown in a container. I'm a Japanese maple collector and grow approximately 30 of my trees, different cultivars, in containers. I like growing these beautiful trees in containers for several reasons. The best reason is that people such as yourself located in colder climates can still enjoy these trees during the spring, summer, and fall and then move them easily to a more protected area during the winter. Potted trees can be placed throughout your patios, decks, and gardens at any time to enjoy wherever and whenever you desire. Potted trees are also easily taken with you if the time comes when you may want to move to another location. Japanese maples in their natural habitat are normally understory trees. They do well under the filtered light of larger trees. Most appreciate afternoon sun as leaves can scorch easily in hot afternoon direct sunlight. In the warmer months of summer I can easily move my potted maples to locations where they receive afternoon shade or filtered light.

The Purple Ghost is hardy to zone 5. When planted in containers a general rule of thumb is the roots of the tree are 2 zones less cold hardy than if the tree was planted in the ground. The chance of the root system freezing above ground in a container is far greater than if the tree was planted in the ground. Because of this you are correct in thinking about growing your Japanese maple in a container.

In the winter you can move your maple to an unheated garage or any protected area where the trees roots won't freeze. Moving the tree out of any freezing wind and wraping the container with a blanket, burlap, or other material would also help to insulate the roots from freezing. You don't want to take your tree indoors or to any area that is too warm. Japanese maples need a good cool dormancy period, a time of rest, to stay healthy and produce a lot of nice new growth each year. Any location that is protected from harsh freezing winds and temperature should be fine.

When planting Japanese maples in containers using a quality potting mix that is well draining is most important. Everone uses what he or she feels is best. Because of this you will fine many good formulas for mixes. Don't let coming up with a good mix confuse you. I have found a simple mix that works well for my Japanese maples is a quality potting soil with a few large handfulls of medium orchid bark and pumice mixed in. The quality of potting soil is important and in my opinion you will only find this at you quality local nurseries and garden centers not the box stores. I have noted a link below to an article in Gardenality that can help you with tips on planting your Japanese maple in containers. Just click on this link to go directly to the article. The article will also help you with tips on choosing a container for your tree.

Depending on the size of your tree will determine what size container you will want to start with. You don't want to start with too large a container. Japanese maples do not like to be kept to wet. Too large a container holding too much soil can hold more water than your maple may need. I normally start with a container that is approximately 4 inches larger in diameter that the existing root ball. As the tree grows you will be potting up every two to three years untill the tree can be grown in a larger container for the rest of its life. After this the tree should be root pruned every 2 to 3 years to keep it healthy and growing in the same size container.

http://www.gardenality.com/Articles/892/How-To-Info/Planting/Growing-Japanese-Maples-In-Containers/Growing-Japanese-Maples-In-Containers.html

Hopefully this has helped with your question.

John)