How to care for an old bougainvillea trunk so it blooms abundantly? Control light and temperature like this
Anyone who grows bougainvillea knows that once an old specimen is well established, it puts on a spectacular show when it blooms, bursting with real presence! But if you want that old plant to grow strong and bloom abundantly, you have to get the details right - light, watering, fertilizing and pruning - and especially guard against pests and diseases ahead of time. How exactly do you do it? Let's go through it bit by bit.
Light and Temperature: The More Sun, the Better
An old bougainvillea is a "sun-worshipping fanatic"6 hours of direct sunlight a day. If the light falls short, the branches and leaves just grow rampant, and blooming is hopeless. Still, when the summer heat is especially intense, shade it a little so the sun does not scorch the leaves. Its comfortable temperature is 15-30°C5°C it may suffer cold damage, so growers in the north must move it indoors for winter, while in the south, where temperatures do not drop so low, a little wind protection will do.
Watering and Water Control: Water Only When Bone Dry, "Starve" It a Bit During Blooming
Water by the "dry-wet cycle": once the soil surface is thoroughly dry, water it thoroughly in one go. Do not be lazy and give only half a watering, or the roots will sit stifled in wet soil and the leaves will drop in droves. If you want it to bloom more, about 20 days before the blooming period you have to "be cruel" and control water— wait until the leaves look a little wilted before watering, and repeat this 2-3 times, and flower buds will appear in abundance. Remember, never water recklessly every few days; the roots of an old plant cannot take that kind of abuse.
Fertilizing and Pruning: The Right Fertilizer, the Right Cuts
During the growing season (spring and summer), give it a balanced nitrogen-phosphorus-potassium fertilizer every 10-15 days to make the branches and leaves grow sturdy. As blooming approaches, switch to a high-phosphorus, high-potassium fertilizer so the flower buds can build up plenty of energy. After the flowers fade, promptly cut off the spent blooms and branches that have grown too dense, so they do not steal nutrients. Before spring budding, prune weak branches and wildly vigorous branches hard; if you want a particular shape, keep the main branches or the top canopy, and also cut away dead twigs and fine branches hidden inside. With good airflow, problems are fewer.
Pest and Disease Control: Spot Them Early, Act Early
Old specimens are prone to aphids and red spider mites; when you spot them, wipe the undersides of the leaves with soapy water or alcohol. For scale insects, first brush them off with a toothbrush, then spray with a pesticide. If it comes down with anthracnose, cut off the diseased leaves promptly and spray a fungicide. Keep the windows open for ventilation regularly; when air circulates, insects and pathogens have a harder time finding their way in.
Things to Note: Potting Up a New Specimen Takes Care
If you have just acquired a new specimen, first cut away all dead branches and rotten roots, soak it in a little carbendazim to disinfect, and let it dry before planting. The soil must be dry; do not use wet soil, or the roots will rot easily. In the north, where the air is dry, slip a bag over it after planting to keep in moisture; in the south, just put it in a spot with indirect light to let it settle, and the survival rate will be much higher.
Actually, an old bougainvillea is not that delicate. As long as it gets enough light, is not watered haphazardly, is pruned when it should be, and you keep an eye out for pests and diseases, it will not be long before it grows lush and full of leaves, and when it blooms the whole plant is covered in flowers - a truly delightful sight!