There is nothing quite like the bright blaze of color provided by bougainvillea. Originally from South America this woody vine grows outdoors in frost free climates in the United States and can be made into beautiful blooming bonsai. The Chinese call it “thorny azalea” because of its thorns and its outstanding floral display resembling azaleas. The flowers are tiny but surrounded by three colorful bracts, the shiny green leaves are slightly hairy, and the young branches and twigs are very pliable and easy to bend. Bougainvillea is suitable for all styles of bonsai except formal upright. It is not frost tolerant and must be brought indoors in cold climates. In summer, however, it must be put outside in order to bloom.
Position: Full sun and warm location during the summer; bright light, airy location with temperatures Between 49o F. and 54o F. in winter so the plant can rest.
Water: Water sparingly in winter never allowing the soil to completely dry out; increase water gradually in spring and water daily and thoroughly when plant is forming buds or flowering. Dunking the pot daily in a tub of water until bubbles stop emerging from the pot is a good way to ensure an adequate water supply in hot summer months.
Fertilizer: Feed once a week with liquid bonsai fertilizer from when plants are in flower and every two to four weeks during the rest of the growing season. Do not fertilize during the winter rest period.
Repotting: Plants should be repotted ever two years in early fall or before active growth begins. Light root pruning should be done at the time of repotting with care be taken because of brittle roots. Bougainvillea need relatively large pots because of their heavy water and nutrient demands.
Soil: Use bonsai soil or a mixture of 70% loam and 30% sand.
Pruning: Prune branches after blooming has ceased, cutting back into the old wood. Pinch back new growth always leaving 2-3 leaves in place. Trim back the tap root and bigger secondary roots when repotting.
Wiring: Wiring of new and last year’s growth can be done any time during the growing season; old, thick, woody branches are brittle and can not be wired.
Propagation: Cuttings and air layering in spring or summer
Comments: Bougainvillea may have problems with aphids and black spot fungus.