Materials For Indoor Bonsai

Introduction

Centuries ago the art of bonsai originated in China and spread to Japan where it underwent much modification prior to its dissemination to the western world. The Japanese use the trees found in their backyards and woods which are native temperate zone species such as pine, maple, beech etc.

In America we have accepted traditional bonsai but we have modified these methods and are using trees previously untried and unknown in classical bonsai for the newly evolving "indoor bonsai" specialty.

Why bother?

The population of the world is moving to urban environments where outdoor growing is difficult. Growing outdoors has problems such as extreme temperature variation, pollution and vandalism. Apartment dwellers, and home renters can grow trees on a window sill or under artificial light. In addition, during winter outdoor trees are in cold storage and unavailable for work and enjoyment; with the addition of an indoor bonsai collection the fun continues year round. Last, indoor bonsai offer non-traditional materials, and the freedom to experiment with styles and flamboyant pots that would be sneered at in traditional bonsai.

Nature never created an "indoor" tree so materials must be able to cope with the rigors of the indoor habitat. Trees must tolerate low light, low humidity, and lack of chilling. Surprisingly few species have been used indoors, and much work needs to be done to determine which plants will survive this hostile environment. Every indoor grower is a pioneer adding to the fund of knowledge about plant survival and suitability. It is vital that indoor bonsai growers communicate their success as well as failures.

Growing Techniques

Trees need light to survive, and even more for growth, flowering and fruiting. Growers can utilize one of several techniques. First, those lucky enough to have a greenhouse have enough light for successful bonsai culture. Two, a south or west windowsill will provide adequate light for many tree species. Three, if natural light is unavailable great success can be had by growing plants under fluorescent tubes. Plants should be as close as possible to the bulbs, as light energy drops drastically even at one or two feet from the tubes. Fluorescent tubes are cool to the touch and leaves will not be damaged by proximity to the bulb. Special plant grow lights may allow better plant growth and flowering.

Simple homemade fluorescent indoor light setup by Cyril Grum

The second critical factor is humidity. Most homes are incredibly dry due to the heating and cooling necessary for human comfort levels. In fact the humidity in our homes is less than the average desert. Plants, excepting cacti, will not grow and flourish in such low humidity. Any technique to humidify the area around the plants will allow better plant growth. Misting and spraying plants frequently helps but is impractical. A humidifier close to the plants may be beneficial. Last, surround the growing areas with a plastic "tent" and increase the humidity around the plants, but don't completely seal plants in plastic since fungus will take over.

Temperature is another important factor in plant growth. In general most plants thrive indoors in a range of 60 to 90 degrees Fahrenheit. Higher or lower temperatures will result in slower growth of some plants or even their death. Varying temperatures from a daytime high and cooling down twenty degrees at night allows materials considered difficult to be grown indoors.

In twenty three years I have culled through plants searching for plants that will tolerate indoor conditions. Some species have been failures and others have been very successful. Following is a list of ten plant species that I have found to be suitable for indoor bonsai and suggestions to allow success with these plants.

Common Name - Scientific Name

1. Chinese Banyan - Ficus microcarpa Click here to view image.

ADVANTAGES

Many varieties available.

Leaves dwarf well in pot culture.

Tolerates heat and dry air.

Excellent root flare and buttress development.

Tolerates pruning well.

Easily grown from cuttings, and air layers.

Aerial roots develop in humid, dark conditions.

DISADVANTAGES

Less useful for small (Shohin) bonsai.

CULTURAL HINTS

Water and fertilize regularly.

Give as much light as possible.

Keep evenly moist.

Avoid temperature below 50 F.

2. Chinese Sweet plum - Sageretia theezans

ADVANTAGES

Twiggy growth.

Small leaf size.

Exfoliating bark - if over 6 years old.

Tolerant of high heat and light levels.

Easily grown from cuttings.

DISADVANTAGES

Difficult to wire old wood.

Collected specimens difficult to re-establish.

CULTURAL HINTS

One of the few plants that never seems to rest; It is always in active growth.

Appreciates even moisture and frequent fertilization.

3. Buttonwood - Conocarpus erectus - Click here to view image

ADVANTAGES

Gorgeous dead wood on collected specimens.

Leaves dwarf with pot culture.

Unusual flowers.

Not fussy as to soil type.

DISADVANTAGES

Requires warmth.

Must never dry out.

Hard to obtain collected specimens.

CULTURAL HINTS

Keep warm and never below 50 Fahrenheit- especially roots.

Soil must be kept moist; never allow to dry out.

Avoid the use of pesticides as toxicity is common.

4. Natal Plum - Carissa grandiflora Click here to view image.

ADVANTAGES

Leaves reduce with cultivation. Smaller leaf cultivars available.

Tolerant of heat and dryness.

Flowers and fruit are attractive.

DISADVANTAGES

Must have a coarse and well-draining soil.

Older wood is brittle and difficult to wire.

CULTURAL HINTS

Plants respond to severe pruning (reduction) with new growth.

Blooms on terminals of new growth; limit hard pruning if flowers/fruits are desired.

Grow the plants slightly drier rather than wetter.

Wire branches while green; woody branches will break.

5. Lantana - Lantana camara

ADVANTAGES

Flowers and fruits easily.

Hardy.

Drought resistant and heat tolerant.

Easily grown from cuttings.

DISADVANTAGES

Brittle branches.

White flies love this plant.

Trunk does not fatten readily in pot culture.

CULTURAL HINTS

Branches are brittle and break easily; if the branch breaks stop immediately and leave wire on until the fracture heals, then cut the wire off.

Yearly repotting is beneficial.

Do not overwater.

6. Pomegranate - Punica granatum

ADVANTAGES

Fruits and flowers.

Vigorous grower.

Dwarf varieties available.

DISADVANTAGES

Winter rest is necessary and some chilling is helpful. But definite cold requirement is not necessary.

CULTURAL HINTS

Allow the plant to go dormant in the fall by keeping the plant cooler and drier. Leaf drop will occur.

Do not fertilize when at rest.

7. Singapore holly - Malpighia coccigera

ADVANTAGES

Small leaves.

Twiggy growth.

Flowers well but rarely fruits indoors.

DISADVANTAGES

Trunk remains small.

CULTURAL HINTS

Keep lightly moist and well fertilized.

Appreciates trace elements in soil mix.

8. Olive - Olea europaea

ADVANTAGES

Small leaves.

Twiggy growth.

Good bark color and texture.

Excellent trunk buttress.

Tolerates heat and dryness.

DISADVANTAGES

Older wood difficult to wire.

CULTURAL HINTS

Avoid constant soil wetness- prefers to go nearly dry before watering again.

Rests during winter but retains leaves.

Wire branches while green and supple.

9. Parsley aralia - Aralia elegantissima

ADVANTAGES

Delicate leaf.

DISADVANTAGES

Brittle branches make wiring difficult.

Roots won't tolerate constant wetness.

Branches irregular and coarse.

CULTURAL HINTS

Let soil dry between waterings.

Watch for insect infestation.

10. Schefflera - Brassaia actinophylla and Dwarf Schefflera

ADVANTAGES

Tolerates low light.

Tolerates low humidity.

Brassaia tolerates dryness. Dwarf Schefflera must be kept moist.

Will form aerial roots under humid conditions

DISADVANTAGES

Large leaf size.

Coarse branching.

CULTURAL HINTS

The plant to try if you have killed everything else!

Following is an encyclopedia of plants that I have grown indoors and suggestions about these materials.

PLANT MATERIALS - ADVANTAGES and DISADVANTAGES

1. Schefflera/ Brassaia 1,2,3, 6

2. Ficus ( Figs) 1,2,3

a. salicaria, salicifolia, nerifolia etc. (Narrow Leaf)

b. benjamina (Weeping fig)

c. microcarpa, retusa (Chinese banyan)

3. Honeysuckle (dwarf)

4. Cotoneaster 2,4, 9

5. Holly (Ilex vomitoria) 4, 6,10

6. Malpighias (punicifolia, coccigera) 2,3,4

7. Sageretia theezans 1,3

8. Cuphea hyssopifolia 4

9. Buttonwood (Conocarpus ) 3,5

10. Serissa foetida 1,4, *Cooler temps may help

11. Citrus sp. 2,3,4, 6,8,9

12. Boxwood (Buxus sp.) 2,6,7,10

13. Pomegranate 1,3,4,6,8

14. Myrtle (Myrtus communis) 1,4

15. Carissa grandiflora 2,3,4, 6

16. Texas ebony 3,6,7

17. Bougainvillea glabra 2,3,4, 6,8,10

18. Crape myrtle 4,8,*

19. Lantana 1,2,3,4,6,8,9,10

20. Olive (Olea europaea) 2,3,6

21. Guava 1,4,5,6

22. Camellia & Gardenia 4,6,9,*

23. Aralia 2,3,6

24. Fukien tea 4

25. Azalea 4,10

26. Junipers *

27. Japanese Black pine 6,8,*

28. Aleppo pine 7

29. Elms (tropical) 1,

30. Jade (Crassula) 2,3,10

31. Hibiscus sp. 1,4,6,10

CODE

1. Vigorous grower

2. Tolerates some dryness

3. Tolerates heat

4. Fruits/ flowers

5. Tolerates excess water

6. Stiff or coarse

7. Slow grower

8. High light required

9. Insect susceptible

10. Brittle -caution wiring!

* May require chilling

References

1. Introduction To Indoor Bonsai, Meislik, J., American Bonsai Society 2006

2. Wonderworld of Tropical Bonsai- Jyotl and Nicunj Parekh

3. Indoor Bonsai- Paul Lesniewicz -Blandford Press

4. Bonsai for Indoors - Brooklyn Botanic Garden Record

5. Growing Bonsai Under Lights - J. Wikle - Light Garden Magazine June 1980