In addition to growing miniature bonsai for indoor enjoyment, some people
prefer the miniature or larger outdoor bonsai tree. With this, you are still
growing the same species of tree, using the same preferred style, but on a much
larger scale or in a different environment. For indoor bonsai, you would
commonly use tropical trees, which work well in an indoor environment or if you
prefer, can be placed outdoors during the late spring or summer. The outdoor
bonsai tree would generally fall within two categories – evergreen trees, which
would include pine and juniper, or deciduous trees, which are trees that lose
their leaves in the fall and then become dormant, followed by springtime
rebudding such as elm. With outdoor species, you can plant them directly in the
ground or keep them in containers.
Outdoor bonsai trees do not do well indoors for a long period and when grown or
placed outdoors, they need to be protected from freezing. When growing outdoor
bonsai, proper watering is probably the most important aspect to success. For
example, with outdoor bonsai, top soil might appear dry but just below the
surface it is still moist. Many times, outdoor trees will go through different
stages after buying so allow your tree to become acclimated to its new
environment for several weeks before making any major changes. At first, the
tree’s leaves may become yellow and fall off but this is just temporary and
nothing to fear.
After the tree is planted, you can check the water level by poking your finger
down in the soil about an inch. If the soil is dry, water thoroughly so the
water flows out from under the container. Typically, the water level would only
need to be measured every two weeks. Then as the warmer summer months approach,
the frequency of watering would likely increase whereas during the colder winter
months, you would water less. Just remember that for your outdoor bonsai tree to
survive in the winter months, you should only water when temperatures are 45 or
above. Anything less could damage or kill the tree.
In addition to water, you need to fertilize your outdoor bonsai tree. For this,
the frequency would depend on the type of fertilizer you are using since some
are more potent than others are. You can check with your local nursery or
gardening center to see what type of fertilizer they recommend. Then, during the
tree’s growing season, you would fertilize every two weeks but keep in mind that
for outdoor bonsai trees, you never want to fertilizer at all during the winter.
Typically, the best application would be to the foliage, allowing the liquid
fertilizer to run down into the soil. In addition to fertilizer, hormone and
vitamin supplements are recommended to keep your tree strong and healthy.
Your outdoor bonsai tree will also need to be trimmed and pruned, the top
elements of growing bonsai. For this, any excess growth would be trimmed away
using special trimmers or sharp shears for deciduous and tropical trees. The
best option is to cut at an angle just above the leaf. To trim evergreen trees,
you would simply pinch back any excess foliage growth. Finally, outdoor bonsai
trees need to be pruned and repotted. The roots of your bonsai tree will need to
be pruned and the tree repotted only after the roots have filled the pot, having
nowhere else to grow. When this happens, the soil will become packed and dry,
making it impossible to water effectively. In most cases, the outdoor bonsai
tree will need to be repotted about every two to three years although this will
vary depending on the species and the speed at which your tree is growing.
Remember, this is a quick and easy process but extremely necessary. Simply
remove about one-third of the root ball, placing the tree back in the container
with fresh bonsai soil.