The art of bonsai began in China over 1,000 years ago and gained popularity as a craft in Japan over the centuries. Bonsai are not a special variety of plant and there is no "bonsai species"; instead, they are normal trees. A bonsai is simply an ornamental tree in a pot, grown and styled to create a miniaturized and sometimes stylized representation of a tree in nature. Although in some cases dwarf trees are used for bonsai, if a bonsai is planted in the ground it will eventually grow into a full-size tree or plant. There are landscape style bonsai; they are generally called Penjing (which is also the Chinese term for bonsai).
 
Some of the most popular deciduous trees include Japanese Maples, Chinese Elm, Japanese Elm, Oak, and Wisteria. These shed their leaves in the fall. Ficus, Dwarf Jade, and Cotoneaster are popular broadleaf evergreen trees. Of all the conifer trees Juniper, Japanese Black Pine and Japanese White Pine, Cedar, Fir, Hinoki Cypress, and Redwood are favorites. Whether a bonsai lives indoors or outside depends on the species. Indoor bonsai trees should generally be tropical and have access to direct sunlight for a large part of the day. One reason Ficus trees are so popular with bonsai beginners is because they can live indoors.

 
Just as there are many different bonsai tree species, bonsai can grow to different sizes. The size class implies the height and weight of the tree in its container, and it's based on the number of people required to move the tree and pot. The very largest size, named Imperial bonsai, is named after the enormous potted trees of Japan's Imperial Palace.

Bonsai Tree Size Classification

The Large Bonsai sizes require the most sets of hands:

• Imperial which is an Eight-handed bonsai, 60-80″ (152-203 cm)
• Hachi-uye which is a Six-handed bonsai, 40-60″ (102-152 cm)
• Dai or Omono, which are each Four-handed bonsai, 30-48″ (76-122 cm)

The Medium-size Bonsai are two-handed:

• Chiu or Chumono or Ōgata, 16-36″ (41-91 cm)
• Katade-mochi or Chuhin, 10-18″ (25-46 cm)

A miniature Bonsai is a small tree that won't take up more than one hand:

• Kumono or Kifu is a One-handed bonsai, 6-10″ (15-25 cm)
• Shohin or Chohin is also a One-handed bonsai, 5-8″ (13-20 cm)
• Mame fit in the palm of your hand, 2-6″ (5-15 cm)
• Shito are Fingertip size, 2-4″ (5-10 cm)
• Keshitsubo are tiny trees, poppy seed size, 1-3″ (3-8 cm)

The shape of a bonsai is created through regular pruning and careful maintenance of the growth of the roots and the leaves or needles. Any species of tree with a permanent wood-like structure, a vine, or a shrub, is a candidate for bonsai. Some cacti, succulents, and pachycaul (like desert rose) can also be used to make bonsai plants. Bonsai is a natural, organic art form that provides joy to bonsai enthusiasts and hobbyists.

Bonsai trees can be planted in ceramic or concrete pots, on stones, or in unique containers. Bonsai containers come in many styles and sizes and must have drainage holes. There are conventions to selecting the proper bonsai pot, depending on the type of tree. One general rule is that the pot’s height should match the trunk’s width above the nebari (roots visible above the soil). The depth of the pot is mostly determined by the girth of the trunk. The size of the pot is determined by the visual weight of the combination of the foliage and trunk. The style of the pot is chosen to match the style of the tree, which is open to interpretation.

The pot is an important component for the overall health and root growth. Using a shallow pot helps to constrict the tree’s roots and prevents the tree from growing too quickly. With a shallow container, the root system is restricted from spreading and expanding. A tree is often repotted from a larger pot into a small pot for similar reasons. As a young tree ages, it might move from a small container into an even smaller bonsai pot! Regardless of the rules, if the combination of a pot and tree brings its owner joy, then the pot selected works with the tree!

Important aspects of proper care that impact a tree's health and growth rate include how much water the tree receives, whether it needs and receives access to full sun, weather during the prime growing season, fertilization, and proper bonsai soil. With good care and the right conditions, a bonsai tree can be expected to experience multiple rounds of new growth each year.

A Few Fun Bonsai Records

• The smallest bonsai in the world (pending, Guinness World Record listing) is a Japanese Maple. It is truly a miniature tree!

• The largest bonsai in the world is believed to be a red pine located at the Akao Herb & Rose Garden in Atami, Japan. It is also one of the oldest bonsai trees. The tree is at least 16 feet tall and 30 feet wide. It qualifies as a bonsai because it’s contained in a pot.  (photo from Akao Herb & Rose Garden)

• One of the oldest bonsai trees in the world is the Ficus retusa Linn (in the fig family). It’s estimated to be at least 1,000 years old and it grows in the oldest bonsai pot. This tree was taken care of by Chinese bonsai masters for a long time before moving to Italy, where it now resides at the Crespi Bonsai Museum.

To learn more about bonsai, visit a public bonsai collection and get an up-close look at high quality trees; join a local bonsai club to connect with other bonsai hobbyists, or sign up for workshops with a bonsai professional. Popular collections include The Bonsai and Penjing Museum at the National Arboretum (Washington, D.C.); The Chicago Botanical Garden (Chicago, IL); Clark Center Bonsai Collection at the Shinzan Friendship Gardens (Fresno, CA); The Bonsai Garden at Lake Merritt (Oakland, CA); The Pacific Bonsai Museum (Federal Way, Washington); the Huntington Botanical Gardens (San Marino, CA); and the James J. Smith Gallery (tropical species) at Heathcote Botanical Gardens (Fort Pierce, FL). The American Bonsai Society has compiled a complete list.

So how big do bonsai trees get? It really is up to the patience, temperament, and preference of the bonsai artist to decide!