Bougainvillea Bonsai Care Guide: What You Need To Know

The bougainvillea sapectabilis is a gloriously coloured ornamental woody shrub with heart-shaped leaves, vibrant petals and thorny stems. The plant is named after the French Navy Admiral Louis Antoine de Bougainville when he and Philibert Commerce, a French botanist, discovered it in 1768 whilst on a global journey. It is indigenous to South America, mainly Peru, Brazil, and Argentina. The bougainvillea likes warm climates as long as there is enough rain. It’s Grenada’s national flower.

Interestingly, the colourful petals that are so well-loved on a bougainvillea are actually leaves or colourful bracts. The tiny flowers are white or yellow, and three to six bracts surround each cluster. However, the bracts are the real showstoppers. They are fondly nicknamed the paper flower because its bracts are thin and papery. Bougainvillea bracts come in a huge colour spectrum ranging from red, purple, magenta, a gorgeous hot pink, light pink, orange, apricot and white. The waxy ‘false flowers’ attract pollinators such as bees to the true and hidden flower.

The bougainvillea ages beautifully; the pale grey truck gets gnarlier with age. They are fast-growing and tolerate pruning particularly well. Bougainvillea is a subtropical plant that can’t endure frost or temperatures below 50° F to 59° F or 10° C to 15° C in winter. The bougainvillea belongs to the four o’clock family, Nyctaginaceae. There are between four and 18 species in the genus and over 300 varieties which are also known as Napoleón, veranera, trinitaria, Santa Rita and papelillo. Many of today’s bougainvillea result from interbreeding, and only three out of the 18 South American species are recognised by botanists.

The sap of bougainvillea can cause severe skin rashes, similar to the Toxicodendron species.

Care Guidelines For Bougainvillea Bonsai

Ideal Placement

The bougainvillea thrives in the sunshine and high temperature. It, therefore, needs to be placed in a sunny part of your garden during the growing season. If you live somewhere that has cold winters, you’ll need to move the bougainvillea into an inside room that has sufficient light during its dormant period. If the plant doesn’t have enough sunlight, it will lead to decreased leaf production.

Ideally, your bougainvillea will enjoy six hours of sunshine each day which will ensure you endless colourful blooms (or bracts).

If you intend to grow your bougainvillea bonsai inside, it should be close to a west or south-facing window. The plant can tolerate fluorescent lighting, but natural daylight is best.

Water Requirements

Your bonsai will respond well to a bit of abandonment and enjoy not being watered too frequently. Water your bougainvillea thoroughly when the soil gets dry by giving it a good soak. Constant watering and soil dampness can lead to leaf drop, root rot, fungal problems, increase susceptibility to insects and lead to possible death. The bougainvillea bonsai prefers pH balanced soil between 6 and 6.5, so avoid watering it with highly calcareous or hard water. Regularly check the soil dampness, soak and water again when it dries out.

Try not to really dry out the bonsai, but if it does happen, set the pot in a bucket of water so that the roots can absorb the water first.

Soil And Fertilizing

You can add nitrogen-rich organic liquid fertiliser to the soil every week or solid, slow-release fertiliser that contains nitrogen, phosphorus, and potassium every month during the growing season. Regular fertilisation will ensure maximum leaf growth and for the bracts to give you a riot of colour. However, it is really important that you choose the right fertiliser.

Whilst it will enjoy nitrogen, too much will stunt your plant’s growth and mean that it won’t fully bloom.

Pruning Times

When the bougainvillea has flowered, you can cut the shoots leaving two leaves on each. In the late autumn or early winter, you can heavily prune the branches and twigs. The bonsai will bud again from the old wood. Make sure to cover large wounds with cut paste as it heals slowly.

During the summer months, refrain from extensive pruning and just maintain the shape that you require. Heavy pruning will stop the growth and prevent the bonsai from flowering. Never prune the tree when it is in its dormant stage.

When pruning, beware of the sharp thorns; they can give you a nasty cut.

Propagation Management

The most successful way to propagate a bougainvillea is from a cutting. This can be carried out using the semi-hardwood. Air-layering is also possible but can be quite complicated even for a seasoned bonsai specialist.

For a cutting, it’s best to do it early to mid-summer, which is in the middle of the growth period. Your cutting should be reasonably green and have some darker woody looking areas. You will make a tiny cut where the stem meets the main branch. As you pull it away, it will leave a small diamond-shaped wound.

When preparing your cutting pot, use relatively fine volcanic sand (pumice) and make sure that it is level and compact enough to support your cutting. Before planting, dip the wound end of the cutting into a rooting hormone which will stimulate root growth. Use a dibble stick to make a hole so that you can insert the cutting without dislodging any of the rooting hormones.

Compact the sand to ensure the cutting is firm. Keep the bougainvillea bonsai cuttings nice and damp either by regular misting and watering or covering with a ‘greenhouse’ cover that will keep in the moisture. You should have healthy roots within a couple of months to start your bonsai training.

Air layering is an advanced technique that forces a tree or branch to form new roots by interrupting the natural stream of nutrients from the existing root system. The tree or branch is intentionally wounded and then protected from drying out to form new roots. When there are sufficient roots to support the new plant, it is separated and potted. Layers usually take around three months but can take several years for the slow rooting species. It’s an ancient practice that requires patience.

Air layering is best carried out in the spring between April and May.

Potential Pests And Diseases

The bougainvillea, thankfully, is relatively pest resistant. The majority of the problems will come from overwatering or lack of light which weakens the plant meaning that it can be attacked by mildew, whitefly, aphids, mealybug, scale or caterpillars. Therefore, it’s essential to action treatment as soon as you see the first sign of disease. If you don’t want to use a regular insecticide formula, you can try neem oil, a centuries-old solution ideal for treating houseplants and bonsai alike. The wash-off also protects roots from fungal problems.

All in all, bougainvillea bonsai tend to be healthy if they are well cared for and in a sunny location.

However, if the plant is overwatered, the roots can suffer from fungal problems that cause death.

Repotting Times

Juvenile bougainvillea should be repotted every two or three years and older specimens between three and five years. The roots are pale yellow, thin and very delicate, so you need to take extra care when you take out the root ball from the pot. You can untangle the roots gently and prune them a little. You’ll need to plan the repotting by watering it well two days before and let it dry out. When transferring the plant, use a well-balanced mixture of sand, pumice and compost-rich soil. As a rule of thumb, your pot should be fifty-fifty organic growing and hard drainage materials.

Repotting allows you to check the health of your plant and ensure that there is no disease or root rot; it also gives you the opportunity for growth. Repotting should be done towards the end of the spring season so that the bougainvillea has time to heal and grow during the summer.

Wiring Your Bonsai

You need to be careful when wiring your bougainvillea; the older branches tend to get very brittle with age, so it is recommended that you only wire the branches that are young and supple. As the bougainvillea reacts well to pruning, you have creative freedom when deciding on its shape. There are several techniques that enthusiasts use to shape their bonsai. You can use clips, weights and wires to train and shape your bougainvillea.

Traditional wiring methods tend to be the most popular. Be careful with the thorns!

Q. How Do You Keep A Bougainvillea Blooming?

A. The trick to keep your bougainvillea blooming is to gently prune it throughout the spring, summer and autumn months. You’ll prune your bonsai in the spring to experience a flush of growth and flowers.

To encourage new blooms, you can cut back new growth at the midpoint of the growing cycle by cutting just above the nodes, encouraging new branching, bracts and flowers. Don’t wait until too late into the season. Other than during the dormant period, throughout the year, fertilise the plants regularly to promote new growth and blooms. Your bougainvillea enjoys sunshine, so ensure that it is placed in a sunny part of your garden.

Q. Can I Grow A Bougainvillea From Cuttings?

A. Yes, you can! The easiest way to propagate a bougainvillea bonsai is by taking a cutting from the bonsai.

First, prepare your potting container with slightly damp potting soil and hard material (pumice) to ensure good drainage. Next, trim a small branch off the mother plant, trim off excess leaves from the bottom of the cutting. Dip the bottom of the cutting into the rooting hormone and then plant carefully in the potting mixture. It is important to keep the soil slightly damp, be very careful not to overwater it, or the plant will rot.

Your new bonsai will have roots between four to eight weeks.

Q. How Do Make My Bougainvillea Bloom?

A. To maintain a healthy bougainvillea bonsai, you’ll need to water it infrequently and feed and prune it regularly. The best fertilisation programme is to use a fertiliser with 12-10-10 parts every two weeks during the growing season and a 2-10-10 fertiliser during winter months. The first number is the amount of nitrogen (N), the second number is the amount of phosphate (P2O5), and the third number is the amount of potash (K2O). These three numbers represent the primary nutrients nitrogen (N), phosphorus (P) and potassium (K).

Finally, regularly and gently prune your bonsai to retain its shape, which will, in turn, promote strong central growth to the trunk.

Q. How Do I Care For Bougainvillea Over Winter?

A. Bougainvillea bonsai winter care is very important for the long-term health of your tree.

The bougainvillea is native to the warm climes of South America, so if you live in a cooler climate, you will need to prepare your bonsai for winterising. They can’t endure frost or temperatures below 50° F to 59° F or 10° C to 15° C in winter. You’ll want to rest your bougainvillea over the winter by forcing it into dormancy which is not its normal state, in its native tropical environment where it grows year-round. It will, however, adapt.

To encourage dormancy, place your plant in a sunny spot inside and away from drafts or where it could possibly get too cold. You just need to ensure that the root ball does not dry out entirely. Then, as the weather starts to warm up, you can slightly increase your watering programme and give it a very gentle prune to encourage new growth. When you are sure that there will be no more cold snaps or frosts, you can take the plant back to your favourite sunny spot in the garden for it to flourish once again.

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