When assessing bonsai trees whether to judge, buy or just reviewing your own, to develop them or set up a display there are a range of criteria that can be considered. Some may be conflictual and there may be many rules, but some rules are always meant to be bent a little or broken.
Here are some pointers to get you started…
General condition / health of bonsai tree
- Good leaf colour if evergreen or when in leaf as a broadleaf
- Even density of foliage if in leaf
- Good vigour
- No damage structural form so no broken branches or stems or missing sections, no wire scars, no unsightly bark or pruning wounds
- No damage to foliage so no split leaves, damaged leaves, wilting, signs of ageing
- Healthy appearance for tree species
- Good density of buds if winter image
Maturity
- Actual age of the tree if authenticated and try to obtain some guide to the age if possible
- Bonsai tree image and the impression is correct for the age presented
- Old age is beautiful and the tree should capture the character of a tree growing in nature
- Stem diameter in proportion to height of tree & spread of crown
- Signs of aging present for species include bark fissures, thick trunk and or well developed crown
- High level of ramification, dense branching structure with balance
- Young trees have ascending branches so the branches near and in the apex can be horizontal or ascend since this is the young part of the tree
Freedom from pests & diseases
Therefore it is important to check for the following pests and diseases:-
- Scale insect
- Mealy bug
- Fungal infections
- Rusts
- Red spider mite
- Vine weevil
- Other pests, diseases, viruses or fungal infections
Origin & difficulty of cultivation
The background and origin of a bonsai tree should be considered and here are a few things to review:-
- Tree species that require higher temperature cultivation like tropical trees
- Tree species that require greater care in watering
- Tree species that are difficult to grow under ‘normal conditions’
- Bonsai cultivated by air layering, grafting alternative root stock or fused form if authenticated
- Bonsai grown from seed if authenticated
- Are Yamadori (collected from wild) with permission and nota protected species in that country
- Are grown from start by exhibitor or trader
Rarity
- Relative rarity of tree species
- Unusual cultivar or variety
Presentation
Look at how the tree is presented and does the presentation do the tree justice?
- Refinement of presentation
- Absence of weeds and algae on the compost surface
- Absence of inappropriate flower remains or leaf debris
- Appropriate top dressing i.e. use of moss
- Foliage clean and free from residues
- Labelling of bonsai tree correct species
- Overall image presented (aesthetics)
- Any wiring or guys should be unobtrusive
Bonsai pot / cultural medium
- Correct colour for bonsai tree – coloured glazed should be used for flowering & fruiting trees & colour to complement flower colour
- Does the style, shape and size of the pot fit the character of the tree?
- Correct dimensions of the pot for the bonsai tree
- Depth of pot should be set by the diameter of the trunk except for cascades
- Width of the pot for tall trees should be 2/3rds the height of the tree
- Width of the pot for short trees should be 2/3rds the spread of the tree
- Bonsai pot and tree in harmony
- Tree should be placed behind the mid line of the pot, & to the left or right of the centre line
- Uprights with little movement = rectangular pots
- Informal uprights = oval or round pots
- Oversize trees = deep rectangular pots
- Cleanliness of bonsai pot
- Level of the tree in the bonsai pot – soil to tree transition
- Stability of tree in pot & pot on display
- Soil should be uniform
- Tree not over or under watered
Bonsai stand / Tokonoma
- Appropriate stand for size of tree and pot
- Suitable colour
- Stand made from suitable material
- Complimentary ornament / ascent
- Scroll if used suitable to design
- Overall impact of Tokonoma
Overall form
- Correct form for tree species (naturalness)
- Tree of accurate size for class
- Scale appropriate (Height of tree 6x diameter of trunk)
- Only one apex
Roots / Nebari
- Nebari present
- Roots should radiate from the flare
- No eye poking roots (directly at viewer)
- Roots should be visible on the surface of the soil.
- Do they look natural?
- Anchor wiring should not be visible
Trunk
- Trunk should flare at base to visually anchor the tree
- Taper correct – it should taper as it ascends (no reverse taper acceptable)
- It should be wider near the base and become gradually thinner toward the top
- Should lean slightly towards viewer and not move back on itself
Style of bonsai
- The informal upright style (Moyogi)
- Slant-style (Shakan)
- Semi cascade
- Drift wood
- Raft-style (Netsuranari)
- Literati style (Bunjin-gi)
- Group or forest style (Yose Ue)
- Broom style (Hokidachi)
- Multi-trunk style (Ikadabuki)
- Shari style (Sharimiki)
- Growing-in-a-rock (Ishizuke)
- Free form style
Flowering / fruiting bonsai trees
- Aesthetically pleasing to the eye
- Fruits firm / flowers fresh
- Good colour of fruit / flower
- Density of flowers or fruits even throughout bonsai tree & do not overwhelm exhibit in size or quantity
- No. of flowers open should be in proportion to the size of the exhibit