A Bonsai Dictionary
Accent plant – A small plant that accompanies a bonsai on
display and should suggest the same place and time of year as
the tree. Often called a companion plant. It may be a dwarf
version of a grass, moss, hosta, small flower or other species.
Adventitious buds - Dormant buds lying under the bark of a
tree that might develop into new branches if branches are lost
above that point on the tree.
Akadama - A traditional Japanese bonsai soil component
composed of red volcanic matter. It is used on many types of deciduous bonsai trees.
Apex - The highest point of the tree. The shapes of trees are often defined by a scalene triangle and the apex will be the
top of the triangle. The Apex of a conifer is often well defined but on deciduous or older trees, it may be defined by the
process can be carried out in stages for most
nursery stock grown in fast-draining nursery mix.
Broad-leaf - Broad-leaved trees are a group belonging to the angiospermsor flowering plants which have seeds enclosed
in an ovary. With notable exceptions, they are deciduous and go dormant from Autumn through to Spring.
Bud - Organ or shoot that contains an embryonic branch, leaf or flower.
Buttress - This is also known as root-flare, where the base of the tree flares outwards giving the feeling of great age and
Bud break - The point at which a bud has opened enough to show a green tip.
Bud pushing - The point at which buds are just beginning to swell in the spring. This is often a good time for repotting
and pruning (expect on plants the flower in the spring).
Cambium Green growth tissue directly below the bark, its increase adds to the girth of roots and stems and results in the
yearly rings on a tree.
Callus Tissue that forms over a wound on a branch or trunk as part of the healing process.
Candle - Name given to the extending bud of a Pine before the new needles open.
Canopy - The collective term for the upper-most branches that form the top of a tree.
Chop stick - One of the more inportant tools for
working on bonsai, though they can be expensive
since you generally have to buy a meal to get them.
The are good for working soil down around the roots
od a newly transplanted tree. It is often worthwhile
having several sizes including a big one for bigger
Chlorosis - Loss of chlorophyll and leaf color as a
result of mineral deficiency.
Collected tree - A tree taken from its natural habitat In the best cases, they have been shaped by the forces of nature
Companion plant – A small plant that accompanies a bonsai on display and should suggest the same place and time of
year as the tree. Often called an accent plant. It may be a dwarf version of a grass, moss, hosta or other species.
Concave cutter – A rounded cutter giving a concave cut
for removing material in a manner that leaves a hollow
spot that can later be filled by callus. Also called a knob
Conifer - Conifers belong to the group of naked-seeded
plants known as gymnosperms. Their seeds are not
enclosed in an ovary. Conifers have leaves which are
needle-shaped or scale-like. With a few notable exceptions,
they are evergreen.
Cut Paste - Any of a variety of products used to seal the
wounds on a tree where branches have been removed and
dead-wood is not desired.
Dead-wood - Wood on a bonsai that is left exposed to give an impression of age and a difficult life to a tree. See jin and
Dessication – Caused by a lack of water; desiccated leaves usually occur when the roots are unable to supply water to
them. This can be the result of forgetting to water. In the winter, frozen soil and a dry windy day can quickly lead to
Deciduous - A plant that sheds its leaves each year in Autumn- this can be a broad-leaved or more rarely, a coniferous
Defoliation -The process of partly or completely removing the leaves of a tree during its early summer growth period to
induce a crop of finer, smaller leaves which can greatly increase ramification. Intentional defoliation can be a useful
process. Inadvertent defoliation by forgetting to water or by a late frost in the spring is to be avoided.
Diagonal cutter – A strait-edged cutter where the blades are
at a diagonal from the handle. Used primarily for heavier
cuts and creating jin. The three sizes shown here are for
very small trees, regular bonsai work, and for exceptionallt
Dieback - Death of growth beginning at tip from disease or
injury. Winter dieback is not uncommon, particularly in
trees that have been pruned too late in the season.
Dissected - Deeply cut into segments or lobes as in the
leaves of some Japanese maples.
Dormant – A period of no growth. All trees are dormant in the winter when temperatures are below about 40 °C and
photosynthesis has stopped. Many trees are dormant during the hot summer months, feeling that it is sufficient just to
stay alive. Permanent dormancy is a state to be avoided.
Dormant oil – One of a variety of water-dispersable oils sprayed on plants to keep aphids and mites under control. Be
warned that application to blue-tinted conifers will turn them green for a period of time. It is frequently applied as trees
are put into winter storage. Follow the application instructions.
Ericaceous - A term referring to acid loving, lime-hating plants. Azaleas are a prime example.
Evergreen - A plant that remains in leaf all year. It should be noted that evergreen trees slowly shed their oldest leaves at
certain times of the year (depending on species) as they are replaced by new growth. These include most conifers and
trees like boxwood and some azaleas.
Foliage pad - A small individual mass of foliage on a branch; sometimes referred to as a cloud. Foliage pads are refined
by keeping the trimmed so that they are individually identifiable. Generally pads should not be vertically aligned
because the upper pad will shade the lower pad.
Girth - The circumference of the trunk of a tree measured at soil level.
Graft – A noun used to describe a tree that has been attached to hardier root stock or root-
stock that leads to a desirable trait in the tree. It is also a verb used to describe the process of
adding branches or roots to an existing tree to enhance the appearance of that tree. Shown here
is an unsightly graft that would not be acce[ptable on a bonsai but is common in yard plants.
Hardy - A term used to describe trees capable a withstanding winter weather. Hardiness
changes from region to region. Descriptions of hardiness on this web site are for the
Internode – The woody growth between two nodes (leaves or leaf-joints). It is generally
desirable to choose trees with short internodes or to maintain short internodes by constant
Jin - A branch of dead wood on a tree or live wood turned into dead wood. A noun, but often used as a verb to describe
the process of stripping bark off a live branch. Not to be confused with gin which is what we drink while working on
Juvenile foliage – Most often seen in junipers, these are the young leaves, often sharp pointed growth of a tree that
produces two distinct shapes of greenery. The second type being mature foliage that is more corded in nature.
Knob cutter – A rounded cutter giving a concave cut for removing material in a manner that leaves a hollow spot that
can later be filled by callus. Also called a concave cutter.
Lateral Growth - Growth to the side as opposed to apical growth. (ie: Short wide trees such as Birds Nest Spruce are
Layering - Ground and air-layering are methods of producing new roots from the trunk or branches of a tree; often used
as a propagation method but also useful for correcting poor surface rots (nebari).
Leader - The main shoot at the top of a tree, usually indicating the uppermost continuation of the trunk. These are very
apparent in young trees but should be less clear in more mature trees.
Lime Sulfur - A chemical used to whiten and preserve a section of stripped branch or trunk in order to preserve a jin or
shari. In this application, it is applied at full strength with a paint brush, avoiding any bark or other live areas of the tree.
It is also used to prevent fungal growth and is used according to instructions. WARNING: This has a very foul odor and
is to be used outdoors only.
Linnaean taxonomy - Biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his Systema Naturæ
(1735) and subsequent works. This is a lot more than you probably want to know.
Family - A group of genera whose members resemble one another in several respects
Genus - Closely related and similar plant species
Specific epithet – This term follows the generic name, and with it, comprises the species name. For example, in
the case of Molinia caerulea-Molinia is the genus, carulea is the specific epithet, and the whole is the name of the
Subspecies - Differs from others of the same species in one or more characteristics. Abrv. subsp.
Variety - Botantical variety differs from others of the species,i.e.flower color. Abrv. Var.
Cultivar - or cultivated variety, is a group of plants under cultivation whose members differ from other members
of the same species in one or more characteristics.
Common name - The name typically used in the nursery trade. These names may vary geographically.
Mature foliage – Most often seen in junipers, these are the secondary more corded foliage that follows the juvenile
sharp pointed growth of a tree that produces two distinct shapes of greenery.
Nebari - Commonly-used Japanese term to describe the surface roots of a bonsai (those that can been seen on or above
the surface of the soil).
New wood - A stem or twig on a bonsai that originated during the current season's growth.
Node - Growth point on a branch or trunk from which leaves, leaf buds and shoots can arise.
Material – Pre-bonsai stock from a variety of sources. It may come from nurseries, vendors at bonsai meetings,
collection from the wild or a neighbor’s yard, or from other bonsai enthusiasts who have taken the unusual step of
reducing their collection.
Mallsai - The trees that appear at the mall periodically and that are sold as bonsai. They are often dead upon purchase or
shortly thereafter. They are the most common cause for the phrase, “I had a bonsai once, but it died.”
Old wood - A stem or twig on a bonsai that originated during the previous season's growth or at an earlier time.
Penjing - The Chinese term for bonsai. Generally more
loosely styled than Japanese trees. They frequently depict a
scene and may be placed on a marble slab to represent water.
Pinching - A technique used in bonsai cultivation for
controlling and shaping the growth of foliage by pulling off
soft new shoots with the finger and thumb in a pinching
motion. It can also refer to very light trimming with scissors.
Pot-bound - The adverse state of a container-grown plant
where the root growth has filled the container to the extent of eliminating all vital air spaces. This is the signal that root-
pruning and repotting is required.
Prostrate - The characteristic growth habit of a plant that naturally tends to grow along the ground instead of upright.
This is the antithesis of apical growth.
Pruning - The process of controlling the shape and growth rate of a tree by cutting back the shoots, stems and branches.
Some low level of pruning is required throughout the life of a bonsai. Very substantial pruning is usually described as
Raceme - A type of elongated flower that is composed of individual stalks all growing from a central stem – for example
the flower type found on wisteria.
Ramification - The repeated division of branches into secondary branches.
Rootball - The large mass of roots and soil visible when a tree is taken out of its pot or pulled from the ground.
Root hook- A tool useful for untangling the roots when a tree is
being repotted. Often long roots will encircle the root ball and this
tool is useful for finding the beginning and end of a root.
Root pruning - The practice of cutting back the roots of bonsai in
order to make room in the container for fresh soil and to encourage
new root growth. One of the failings of beginners is to remove
enough roots during the repotting process.
Rootstock - The root system and main stem to be used as the base
of a new tree when propagating through grafting. Many nursery Japanese maples and pines are on rootstock that differs
from the top of the tree.
Scion - The small section of a tree which contains all of the desirable characteristics of the parent tree that will be
propagated into a new tree through grafting on top of the rootstock.
Scissors – The most useful tool for maintaining the styling of a tree. Most scissors useful for bonsai have large rounded
handles that fit the hand well.
Seasonal Bonsai - Species that look their best for a short period of the year, for instance trees grown for their flowers or
fruit. Witch Hazel are the first blossoms of spring, but their leaves are too large the rest of the year. Wisteria are often
grown only for their blossoms.
Shari - Deadwood on the trunk of a bonsai (as opposed to Jin which is a deadwood branch or protrusion).
Style – The Japanese have classified trees into a variety of styles and they use a specific nomenclature. Please see the
accompanying page on styles for both the Japanese and English nomenclature.
Styling - The process of substantially altering the shape of a tree by cutting and wiring the branches of a tree.
Size – The Japanese have classified trees into a variety of sizes and they use a specific nomenclature. Please see the
accompanying page on size for the Japanese nomenclature and English descriptions.
Soil – Not to be confused with dirt. Bonsai soils used for growing bonsai are special mixes of larger-grained materials
designed for good water drainage. Organic soils are those that contain ingredients derived from plants; peat, bark or leaf
litter. Inorganic soils contain inert materials, mineral, stone or hardened/fired clays such as grit, sand, akadama, kanuma,
Suiban - A shallow tray with no drainage holes that is commonly filled with either gravel or water and can house rock
Suiseki - Stones that appear to look like large boulders or mountains and represent the spirit or essence of each;
sometime used in a formal bonsai display. See the Ameriseki portion of this website.
Sumo – An unofficial, coined term for particular bonsai, usually small, that have an exceptional girth and taper in the
Sphagnum moss - Long-fibered moss used for layering or other situations where water is to be retained. Itshould not be
a component of a bonsai soil mix.
Tokonoma – A traditional display area in a Japanese house. Frequently, bonsai are brought inside for a short period to
be displayed with accent plantings and calligraphy.
Tools – The four primary tools for bonsai styling are a saw, scissors, diagonal cutters and knob cutters. Of course, these
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educational purposes. If large portions are copied, we would appreciate attribution. We welcome links to this site.