Growing trees on a balcony. Part 1.

While working at a garden centre I was often asked about growing trees on a balcony. Secretly I thought that must be a special type of torture to confine such big plants to small spaces. I wish I had had the booklet by C. von Walden and L. B. Sjölund at hand then. Not only for their practical knowledge on the subject, but for then I'd have known how beautiful small-growing trees can be on a balcony. Since the booklet is in Swedish l thought I'll share their tips with you.

The basics of letting a tree grow in a container are:

• Choose a small-growing tree suited to the amount of sunshine / shade on the balcony.
  
• A crafted tree benefits from a support such as a bamboo stick.
• The bigger the container, the better (as long as the weight of the tree, container and the soil don't go over the carrying capacity of the balcony, that is). The size of the tree top reflects the size of the root stock, which can help in choosing the container. The minimum size is 50 l.
• Of the container materials wooden, concrete, zinc, rubber and fiberclay pots are fine. Clay pots absorb moisture and thus don't protect the roots from freezing during the winter that well. Also the container needs to have a hole for drainage.
  
• Trees need a lot of water = watering. On a sunny summer day be prepared to water twice a day. On a windy location the tree dries faster, so place it on a sheltered spot. The size of the container is important for the watering also; the bigger the container, the easier to keep the soil from drying.
• The first year fertilise the tree with a slow-release fertiliser. The next year supplement that with liquid fertiliser also. If you have fresh cut lawn clippings, cover the soil with that. It fertilises and helps the soil keep moisture.
  
• Replace the top soil with new soil every spring. It's good to take the tree out of the container every third year and prune the roots and change as much of the soil as possible.
• Cutting instructions are the same as for a tree in a garden. Cutting can be more heavy to keep the tree compact.

For how to keep the container trees alive through winter, and some specific plant suggestions, please be patient, I'll return to the subject.