Bougainvillea Evergreen Climbing Shrub: How to Grow It, Precautions, and the Best Month for Cuttings

Bougainvillea, also known as: paperflower, three-leaf bougainvillea, hairy bougainvillea, lè dù juān (Bougainvillea spectabilis), triangle flower, leaf flower, leaf plum, paper flower, South American purple jasmine, etc. It is an evergreen climbing shrub. It is often used for hedges, courtyard flowering trees and shrubs, and more. So what are the cultivation methods and precautions for bougainvillea? Which month is best for cuttings?

Cultivation methods for bougainvillea (basic knowledge):

1. Best propagation time: the cutting season is generally suitable from March to June. In Hangzhou, late May to early June, before the plum rain season begins, is the best time for cuttings.

2. Best growing soil: bougainvillea is not strict about soil, tolerates barren and dry conditions, and dislikes waterlogging. A sandy soil rich in humus, loose, fertile and highly permeable is best; clay soil should be avoided.

3. Growing humidity requirements: when growing bougainvillea, the potting soil needs to be kept in a moist state.

4. Best growing temperature: the suitable growing temperature for bougainvillea is 15-30°C. In summer it should be properly shaded or measures such as misting and ventilation should be taken, and in winter the ambient temperature should be maintained at no lower than 5°C.

5. Best growing light: throughout the year, except that newly potted young seedlings should first be placed in a semi-shaded place. In winter it should be placed by a south-facing window, and the light duration must not be less than 8 hours.

Growing bougainvillea in pots

Precautions for growing bougainvillea:

1. Potting soil selection

The growing soil is made by piling loam, cow dung, leaf mold, sand and so on to decompose, and adding an appropriate amount of bone meal when used. When planting, bougainvillea should be planted upright, the growing soil should be firmed in, and water should be given thoroughly. During cultivation, pinch out the growing tips regularly to form a bushy, low plant shape. A support can also be set up to let it climb upward.

At home, the following soil formulas can be used: garden soil : leaf mold : sand = 5:3:2; peat soil : leaf mold : sand : perlite = 5:2:2:1.

2. Watering method

Bougainvillea likes moist soil and fears waterlogging. In spring, as growth accelerates, it needs watering every day, and its leaves and surroundings should often be sprinkled with water to increase air humidity; if air humidity is insufficient, it easily drops its leaves. Bougainvillea has many leaves and consumes a large amount of water in summer, so it is best to water once in the morning and once in the evening each day to keep the soil in a moist state, and to increase the frequency of sprinkling water on its leaves and surroundings. After the weather turns cool in autumn, keeping the potting soil moist is sufficient. In late autumn, winter and early spring, when temperatures are relatively low (around 10°C), water less to keep the potting soil on the dry side. But if the indoor temperature is kept above 15°C, watering should be more generous to keep the potting soil moist.

3. Fertilization management

Bougainvillea likes fertilizer. After the weather warms up in spring, apply nitrogen fertilizer once about every 15 days; during the growing season apply cake fertilizer water once a week, and apply phosphate fertilizer several extra times during the flowering period. In summer, apply some liquid fertilizer lightly, and if conditions permit, use a 0.2%-0.3% potassium dihydrogen phosphate solution as a foliar top dressing once every half month. In the early stage of flower branch growth, apply urea once more to favor flower branch growth. After autumn turns cool, reduce the amount of fertilizer, and stop fertilizing in winter.

During the peak growing and flowering season, spray the leaves with 1000-times potassium dihydrogen phosphate solution 2-3 times, or add Yuhong Shiguang microbial inoculant once a month. In late autumn, winter and early spring, when temperatures are relatively low, do not fertilize. But if the temperature is above 15°C, apply mixed liquid fertilizer once every month. Bougainvillea is very sensitive to urea; improper fertilization may produce the phenomenon of luxuriant branches and leaves but few flowers, so be especially cautious when applying urea.

4. Temperature and light

The suitable growing temperature for bougainvillea is 20-30°C. In winter, when the temperature is below 5°C, it is prone to cold damage and leaf drop. Bougainvillea likes light; insufficient light during the growing season will cause the plant to grow weakly and affect flowering. In winter it should be placed in a bright place, and daily light must not be less than 8 hours, otherwise heavy leaf drop easily occurs.

5. Shaping and pruning

Bougainvillea drops many leaves and flowers during the flowering period, and after flowering it needs shaping and pruning. Potted plants are often pruned into a round-headed canopy or tied into shapes, requiring many branches and dense flowering to form a gorgeous canopy. Ground-planted ones need a support set up so they can climb onto it. New branches should be pinched out regularly. After repotting, prune some overly dense branches, leggy branches, dead branches and diseased or pest-damaged branches to encourage more new branches. In July-August, pinch out the growing tips to control growth and promote flower bud formation and abundant flowering. For plants 5-6 years old, a one-time renewal by heading back or heavy pruning is needed.

6. Precautions for planting bougainvillea

Bougainvillea is a light-loving plant; whether potted or ground-planted, it needs plenty of sunlight. Plants treated with strong sunlight have shorter internodes, grow solidly, produce many flowers, have deeper flower color and a longer flowering period. Insufficient light causes new branches to grow weakly, leaves to be dull in color, and few or no flowers.

For bougainvillea bonsai, rectangular or oval purple clay pottery pots or glazed pottery pots are often chosen; the color should not be too dark, so as to set off the brilliance of the bougainvillea bracts. The potting soil should be a nutrient soil rich in humus, loose and well-drained; choose a period in spring when the temperature is relatively stable for potting up.

Bougainvillea is not cold-tolerant; in winter, when the temperature is below about 7°C, it will drop its leaves. However, those that drop leaves in winter will sprout leaves and grow again after the temperature rises in spring, but their growth will be poor. Therefore, the indoor temperature in winter is best kept at around 10°C. In winter, bougainvillea should be placed by a windowsill with ample light, and water and fertilizer management should be adjusted according to different temperatures. Several times a day, mist around it to increase air humidity.

What to do if bougainvillea does not bloom?

1. Unsuitable light.

For bougainvillea, branches that receive plenty of sunlight bloom abundantly, while those that receive little sunlight do not bloom or bloom sparsely. If bougainvillea is kept for a long time indoors with insufficient light or in a shaded spot on a balcony, this is the main reason it does not bloom.

Solution: bougainvillea must be placed in a spot with ample light and good ventilation, letting it receive 8 to 12 hours of light per day.

2. Improper fertilizer and water

Bougainvillea needs sufficient fertilizer and water during the growing period so the plant grows robustly. If fertilizer and water are lacking, the plant will grow poorly, and it is also easy to cause few or small flowers, with poor flower quality.

Solution: according to the size of the pot, generally once a month; during the vigorous growth period of bougainvillea, apply liquid fertilizer once every half month, and apply more when the ambient temperature is higher. Applying more phosphorus and potassium fertilizer favors flower bud differentiation and ensures robust flower buds.

3. Improper watering

There is a saying: “frequent water, no flowers; little water, flowers keep coming.” Water control can make the flower bud differentiation of bougainvillea largely influenced by the amount of water

Solution: during the summer growing season, appropriately increase the amount of watering to promote branch and leaf growth. Around mid-August, control water 3-4 times at the right time to promote the transition from vegetative growth to reproductive growth and speed up flower bud differentiation; when flower buds appear in the leaf axils of branch tips, increase the amount of watering, otherwise growth and flowering will be affected; after October, temperatures drop and water demand is low, so water according to the soil; in winter, move bougainvillea indoors for care, and the watering principle is not to water if not dry, and when watering, water thoroughly.

4. Improper pruning

If bougainvillea has too many and too dense branches, nutrients will be dispersed and flower buds cannot be promoted.

Solution: after flowering, prune moderately, cutting off the pedicels and cutting back 1/3 of the flower branches, and thinning out weak branches, short branches and inner canopy branches. In winter, prune together with repotting and soil changing; pruning should master: short, heavy, thin. Short means heading back, retaining 1/3 of the branch; heavy means heavy pruning of long flower branches; thin means thinning out weak branches so they regrow strong branches, also called renewal pruning; the cut branches can be kept as cuttings for propagation.