How to Care for and Maintain a Bonsai Tree

Jade plant bonsai in ceramic rectangular planter with stones

 Joe Mud / Flickr / CC BY-NC-SA 2.0

Bonsai trees have a reputation for being extremely delicate and difficult to maintain. While these specimens do require special attention, once you learn the principles of bonsai care, it's fairly straightforward.

Bonsai is a Japanese word that literally means "planted in a container". It refers to the practice of keeping large plant specimens, usually trees, from reaching their natural size by a process referred to as "artificial dwarfing."

Many gardeners are familiar with the concept of dwarf specimens of trees or shrubs. For example, semi-dwarf or dwarf fruit trees are bred to grow to between 1/3 to 1/2 their normal size. Such trees can be very useful for orchard fruit production and urban growing in small spaces.

But bonsai are not really dwarves. Instead, they are like a miniature version of a tree that is trained, pruned and maintained in a way that makes it look like a much smaller version of its full size.

These specimens often have a magical, fairy-tale quality about them, hence the popularity and renown of bonsai as a botanical art form.

Their special needs arise from the importance of recreating their parent tree's ideal conditions, which may include certain levels of light, humidity or soil nutrition important for vibrancy and longevity. Proper pruning is also important to maintain the tree's shape and encourage flowering and fruiting at the right time.

Bonsai gingko tree with green leaves turning yellow in blue shallow dish planter
This gingko tree bonsai specimen at the Brooklyn Botanic Garden shows the tree's moment of autumn color transition from green to gold.  Donald / Flickr / CC BY 2.0

Bonsai Tree Selection

Selecting the right bonsai for your situation is important to ensure you can care for it effectively. There are easy, low-care bonsai varieties such as ficus and jade. You can choose a deciduous, sub-tropical or tropical bonsai tree, and read up on the different specific ways to take care of it.

Consider your local conditions too. Is your backyard naturally sunny in winter? That might be a plus for a deciduous bonsai specimen. Do you hot and humid summers? Then a sub-tropical tree should do fine for you. Do you have a sunny bay window that gets bright light on a winter afternoon? Then you can grow a tropical bonsai tree that you can bring indoors for the winter.

A bonsai is not just meant to survive but to flourish with beauty. It's not just a plant but a work of art. With that in mind, here are some tips for caring for your bonsai.

Indoors or Outdoors?

If your bonsai is a deciduous tree, it will benefit from being outdoors, in order to be exposed to the natural weather conditions it is suited to. If a deciduous tree is kept indoors (even a miniature one) it won't get the exposure to cold necessary for its season of dormancy in winter. This is an important part of the tree's growth cycle.

Your bonsai tree will also benefit from the gradual increased exposure to sunlight that occurs naturally with the seasons. With that in mind, you will still want to protect your bonsai from extreme weather conditions or possible damage. So, if there's a storm in the forecast, shelter your bonsai from the wind, heavy rain or snow by placing in under an awning, or bring it indoors for the duration of the bad weather conditions.

It is possible to grow a deciduous bonsai indoors year-round, but it will benefit from a natural light source and plenty of fresh air, so placing it in a sunny window is the best location.

If your bonsai is a tropical plant, but you live in a growing zone that gets cold winters, you will have to move your indoors for a few months until the danger of frost has passed. You'll also need to be very careful to make sure your bonsai gets adequate moisture and humidity, which can be adversely affected by indoor heating systems.

Water and Humidity

One of the trickiest parts of caring for bonsai is getting the amounts of watering and humidity just right. Traditionally bonsai are kept in small pots without much room for soil nutrients or moisture retention. Constant monitoring and appropriate watering or misting is important. You're essentially creating a microclimate for your bonsai.

Watering as needed is better for your bonsai than watering on a set schedule. This is especially important for indoor bonsai as it helps mimic outdoor weather conditions. One good way to make sure your indoor bonsai gets adequate humidity is to place a shallow dish of water nearby. Opening a window to let in the fresh air also helps humidity levels.

Light

Bringing your bonsai indoors for the winter means making sure it gets enough natural light. Even in winter when there are fewer hours of daylight, the intensity of sunlight is much brighter outside than it is inside. The best thing is a sunny window that gets several hours of daylight. If your bonsai is tropical or sub-tropical, avoid a drafty window, as the cold may injure the foliage.

Bonsai can do very well indoors on a year-round basis if you make sure it's light and water requirements are taken care of. But consider giving your bonsai a little outing from time to time, for some fresh air, a light mist of raindrops, or some dappled sunlight, and it will surely thank you with its renewed vigor.