The cultural practices applicable in growing potted bamboo are basically the same as with other potted plants. Where miniature bamboos or bamboo bonsai are desired, the sizes of the plants can be further reduced by applying bonsai techniques.
The following methods in growing bamboo in pots or containers are recommended as a basic guide:
1. Select a suitable container. The two most special considerations are the depth and size of the pot in relation to the planned size of the clump and height of the bamboo plants. Where there is no intention to limit the growth of bamboo, the pot can be as deep and wide as it can be. But where the plants are intended to be grown as bamboo bonsai or dwarf bamboo, the pot should be shallow and small.
Provide drainage holes at the bottom. In ordinary plant pots the holes can be covered with stones or fragment of a clay pot to prevent the medium from leaking out. In bonsai pots, plastic mesh is used, fixed in place with plastic coated wire hooked on to the outside of the tray. Spread a layer of pebbles or coarse sand at the bottom.
2. Prepare the potting medium. In general, the mixing ratio is 1:1:1 clay loam soil, fine river sand and compost by volume. Use a ripe compost.
3. Carefully remove the bamboo plant from the original pot and transplant into the prepared container, singly or in group of clumps, following the landscaping plan. Add potting mix up to the root collar and apply pressure to slightly compact the medium. Sprinkle water immediately but in small repetitive doses until the entire potting medium becomes moist.
4. To ensure survival especially when the soil
holding the roots is crumbled, provide high humidity under shade for at
least 7 days. This can be done by placing the potted plants in a large
plastic bag or in a miniature plastic greenhouse or propagation
5. Grow the potted bamboo under reduced light intensity. If possible, grow moss over vacant spaces surrounding the bamboo clumps to prevent rapid evaporation of water from the soil surface. The color and vigor of the moss plants will also serve as indicator of the sufficiency or excessiveness of light and water. If the moss plants turn brown and start to die, light intensity may be in excess or water has become scarce.
6. Check the potted bamboo plants daily for water needs especially with small pots. During dry months, the watering frequency may be 3 times a day. Apply water repeatedly in small doses until the entire potting medium is permeated. To better ensure proper watering, submerge the entire pot in a basin of water until bubbles disappear. For bonsai plants, soft water such as distilled water or rain water is generally recommended.
7. Fertilize the bamboo plants at regular interval. This can be done weekly or monthly or in longer duration depending on the strength of the fertilizer solution and on the fertilizer material to be used. To be on the safe side when using chemical fertilizers, start with dilute solutions. For example, 1 tablespoon of a 1:1 mixture of complete fertilizer (14-14-14) and urea (45-0-0) can be dissolved in 1 gallon of water. Apply as drench on the soil surface.
8. Control insect pest manually or by using either chemical or botanical insecticide depending on preference. Insect pest control is rarely a necessity in field planted bamboo but it is in potted bamboo in which the most obvious insect pest is the mealy bug. These are sucking insects with whitish color. They are frequently seen on the culms and branches, appearing like cotton balls with sizes proximating that of the cotton bud. They always occur together with ants which protect them and their eggs by creating shelters on the culm made of dried mud. These insects are also found underground, clinging to the roots of the bamboo plants.
Where infestation is minimal, the mealy bugs can be removed manually by picking them with the use of a cotton bud wetted with alcohol. Otherwise, insecticidal spray should be done. In severe infestation, the entire culm need to be uprooted to sanitize the underground parts or an insecticide solution is drenched.
Although the bamboo plants tend to be dwarf in stature because root
expansion is restricted by the pot, the dwarfing effect can be further
induced by regular removal of the tipmost unopened leaves.
(click to read Making Dwarf Buddha Belly Bamboo)
10. Formulate a regular plan for repotting and root pruning. Both running and clumping bamboo need to be lifted from the pot when they become pot bound or root bound. As a general guide, this may be done once a year. 30% to 50% of the soil surrounding the bamboo roots are removed and the old roots are cut with the use of a pruning shear. The effect of root pruning is to promote the regeneration of new roots and root hairs so that the plant will become more efficient in absorbing water and nutrients.
Then return the bamboo plants to the same potting container or replant into another pot. Fill the pot with new potting mixture. This new medium replaces the old one which is already depleted of fertility.
11. For bamboo species where interspecific transformation is frequent like buddha belly bamboo (Bambusa ventricosa), practice rouging by quick removal of offtypes. The rhizome from which the offtype culm originated should be removed.
Treat the potted bamboo like one planted on the ground by thinning out
excess plants and by harvesting old culms. Peripheral growth can be
removed by slicing towards the bottom of the pot.
(click to read Clumping Bamboo Plant Care)
Note: Non-bonsaists may tend to believe that bonsai is induced by starving the plant. This is not so. Bonsai trees are meant to be healthy and to last for generations. Therefore, they must be provided with the best conditions for growth including water supply and proper nutrition. This applies also to the care of dwarf, potted bamboo.
(Ben G. Bareja 2010)